moby--moby/libnetwork
Mark Feit 3a938df4b5
Make the network allocator handle IPv4 blocks too small for network/broadcast addresses.
This was originally in docker/libnetwork#2624, which has been closed since the
code was moved here.

When creating a new network, IPAM's address allocator attempts to reserve the
network and broadcast addresses on IPv4 networks of all sizes. For RFC 3021
point-to-point networks (IPv4 /31s), this consumes both available addresses and
renders any attempt to allocate an address from the block unsuccessful.

This change prevents those reservations from taking place on IPv4 networks having
two or fewer addresses (i.e., /31s and /32s) while retaining the existing behavior
for larger IPv4 blocks and all IPv6 blocks.

In case you're wondering why anyone would allocate /31s:  I work for a network
service provider.  We use a lot of point-to-point networks.  This cuts our
address space utilization for those by 50%, which makes ARIN happy.

This patch modifies the network allocator to recognize when an network is too
small for network and broadcast addresses and skip those reservations.

There are additional unit tests to make sure the functions involved behave as expected.

Try these out:

 * `docker network create --driver bridge --subnet 10.200.1.0/31 --ip-range 10.200.1.0/31 test-31`
 * `docker network create --driver bridge --subnet 10.200.1.0/32 --ip-range 10.200.1.0/32 test-32`

My installation has been running this patch in production with /31s since March.

Signed-off-by: Mark Feit <mfeit@internet2.edu>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2021-10-27 13:03:19 +02:00
..
bitseq refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
cluster Switch from x/net/context -> context 2018-04-24 14:57:04 -07:00
cmd refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
config refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
datastore libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
diagnostic pkg/signal: move signal.DumpStacks() to a separate package 2021-07-15 18:09:43 +02:00
discoverapi fix nits in comments and log 2016-10-29 19:35:18 +08:00
docs Update design.md 2020-02-18 17:21:39 -08:00
driverapi libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
drivers refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
drvregistry libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
etchosts refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
hostdiscovery libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
idm libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
internal libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
ipam Make the network allocator handle IPv4 blocks too small for network/broadcast addresses. 2021-10-27 13:03:19 +02:00
ipamapi libnetwork/ipamapi: godoc fixes 2021-08-27 16:52:46 +02:00
ipams refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
ipamutils libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
iptables Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
netlabel libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
netutils Merge pull request #42777 from thaJeztah/update_go_1.17 2021-08-26 21:24:23 +02:00
networkdb refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
ns Revert "Adjust LockOSThread" 2019-08-15 14:44:03 -07:00
options libnetwork: remove unused "testutils" imports 2021-08-18 14:20:37 +02:00
osl refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
portallocator Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
portmapper refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
resolvconf refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
support Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
test/integration libnetwork: remove CircleCI config and code 2021-06-09 12:31:52 +02:00
testutils Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
types libnetwork/types: remove TransportPort.FromString() as it's unused 2021-08-27 14:16:32 +02:00
.dockerignore Added back dockerignore 2018-06-22 16:10:22 -07:00
.gitignore Added back dockerignore 2018-06-22 16:10:22 -07:00
CHANGELOG.md Spelling fixes 2018-07-12 12:54:44 -07:00
README.md libnetwork: remove CircleCI config and code 2021-06-09 12:31:52 +02:00
agent.go Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
agent.pb.go Gracefully remove LB endpoints from services 2018-03-16 15:19:49 -04:00
agent.proto Gracefully remove LB endpoints from services 2018-03-16 15:19:49 -04:00
controller.go Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
default_gateway.go Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
default_gateway_freebsd.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
default_gateway_linux.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
default_gateway_windows.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
drivers_freebsd.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
drivers_ipam.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
drivers_linux.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
drivers_windows.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
endpoint.go endpoint: remove redundant doUpdateHostsFile() function 2021-06-09 22:38:34 +02:00
endpoint_cnt.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
endpoint_info.go Fix gosec complaints in libnetwork 2021-06-25 18:02:03 +02:00
endpoint_info_unix.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
endpoint_info_windows.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
endpoint_test.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
error.go Merge pull request #1616 from chchliang/testnetwork 2017-04-10 13:54:44 -07:00
errors_test.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
firewall_linux.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
firewall_linux_test.go Skip libnetwork integration tests on Windows 2021-06-02 16:53:29 +00:00
firewall_others.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
libnetwork_internal_test.go Skip libnetwork integration tests on Windows 2021-06-02 16:53:29 +00:00
libnetwork_linux_test.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
libnetwork_test.go fix TestInvalidRemoteDriver() to check underlying error 2021-10-25 14:57:18 +02:00
libnetwork_unix_test.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
libnetwork_windows_test.go Skip libnetwork integration tests on Windows 2021-06-02 16:53:29 +00:00
network.go libnetwork: fix some linting issues 2021-08-27 16:52:44 +02:00
network_unix.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
network_windows.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
resolver.go libnetwork: some minor refactoring / cleanup 2021-10-15 15:26:15 +02:00
resolver_test.go Skip libnetwork integration tests on Windows 2021-06-02 16:53:29 +00:00
resolver_unix.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
resolver_windows.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
sandbox.go Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
sandbox_dns_unix.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
sandbox_dns_windows.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
sandbox_externalkey.go
sandbox_externalkey_unix.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
sandbox_externalkey_windows.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
sandbox_store.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
sandbox_test.go Skip libnetwork integration tests on Windows 2021-06-02 16:53:29 +00:00
service.go Fix libnetwork imports 2021-06-01 21:51:23 +00:00
service_common.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
service_common_test.go Skip libnetwork integration tests on Windows 2021-06-02 16:53:29 +00:00
service_linux.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00
service_unsupported.go Update to Go 1.17.0, and gofmt with Go 1.17 2021-08-24 23:33:27 +02:00
service_windows.go windows: remove redundant init() 2021-06-10 18:00:00 +02:00
store.go Merge pull request #42545 from steffengy/master 2021-07-29 09:29:34 -07:00
store_linux_test.go Fixup libnetwork lint errors 2021-06-01 23:48:32 +00:00
store_test.go refactor: move from io/ioutil to io and os package 2021-08-27 14:56:57 +08:00

README.md

libnetwork - networking for containers

Libnetwork provides a native Go implementation for connecting containers

The goal of libnetwork is to deliver a robust Container Network Model that provides a consistent programming interface and the required network abstractions for applications.

Design

Please refer to the design for more information.

Using libnetwork

There are many networking solutions available to suit a broad range of use-cases. libnetwork uses a driver / plugin model to support all of these solutions while abstracting the complexity of the driver implementations by exposing a simple and consistent Network Model to users.

package main

import (
	"fmt"
	"log"

	"github.com/docker/docker/pkg/reexec"
	"github.com/docker/docker/libnetwork"
	"github.com/docker/docker/libnetwork/config"
	"github.com/docker/docker/libnetwork/netlabel"
	"github.com/docker/docker/libnetwork/options"
)

func main() {
	if reexec.Init() {
		return
	}

	// Select and configure the network driver
	networkType := "bridge"

	// Create a new controller instance
	driverOptions := options.Generic{}
	genericOption := make(map[string]interface{})
	genericOption[netlabel.GenericData] = driverOptions
	controller, err := libnetwork.New(config.OptionDriverConfig(networkType, genericOption))
	if err != nil {
		log.Fatalf("libnetwork.New: %s", err)
	}

	// Create a network for containers to join.
	// NewNetwork accepts Variadic optional arguments that libnetwork and Drivers can use.
	network, err := controller.NewNetwork(networkType, "network1", "")
	if err != nil {
		log.Fatalf("controller.NewNetwork: %s", err)
	}

	// For each new container: allocate IP and interfaces. The returned network
	// settings will be used for container infos (inspect and such), as well as
	// iptables rules for port publishing. This info is contained or accessible
	// from the returned endpoint.
	ep, err := network.CreateEndpoint("Endpoint1")
	if err != nil {
		log.Fatalf("network.CreateEndpoint: %s", err)
	}

	// Create the sandbox for the container.
	// NewSandbox accepts Variadic optional arguments which libnetwork can use.
	sbx, err := controller.NewSandbox("container1",
		libnetwork.OptionHostname("test"),
		libnetwork.OptionDomainname("docker.io"))
	if err != nil {
		log.Fatalf("controller.NewSandbox: %s", err)
	}

	// A sandbox can join the endpoint via the join api.
	err = ep.Join(sbx)
	if err != nil {
		log.Fatalf("ep.Join: %s", err)
	}

	// libnetwork client can check the endpoint's operational data via the Info() API
	epInfo, err := ep.DriverInfo()
	if err != nil {
		log.Fatalf("ep.DriverInfo: %s", err)
	}

	macAddress, ok := epInfo[netlabel.MacAddress]
	if !ok {
		log.Fatalf("failed to get mac address from endpoint info")
	}

	fmt.Printf("Joined endpoint %s (%s) to sandbox %s (%s)\n", ep.Name(), macAddress, sbx.ContainerID(), sbx.Key())
}

Contributing

Want to hack on libnetwork? Docker's contributions guidelines apply.

Code and documentation copyright 2015 Docker, inc. Code released under the Apache 2.0 license. Docs released under Creative commons.