No name check when there is a dot in service name

Description
When deplay a service with name "test.com", daemon will return a error.
Shall we need to check the service name in cli? Or update daemon's check to allow dot in service name?

Steps to reproduce the issue:

1. create file4.yaml with the content in description.
2. docker stack deploy -c file4.yaml stk4

root@iZ2ze0tktsnis7mhjiyab1Z:~# cat file4.yaml 
version: "3"
services:
  test.com:
    image: redis

root@iZ2ze0tktsnis7mhjiyab1Z:~# docker stack deploy -c file4.yaml stk4
Creating service stk4_test.com
failed to create service stk4_test.com: Error response from daemon: rpc error: code = InvalidArgument desc = name must be valid as a DNS name component

Describe the results you received:
Creating service stk4_test.com
failed to create service stk4_test.com: Error response from daemon: rpc error: code = InvalidArgument desc = name must be valid as a DNS name component

Describe the results you expected:

Service with name "test.com" is not allowed.  Only characters like "^[a-zA-Z0-9](?:[-_]*[A-Za-z0-9]+)*$" are allowed.

Or:

Creating service stk4_test.com
Service stk4_test.com created successfully.

Or:

It's not important. Don't need change anything.

Additional information you deem important (e.g. issue happens only occasionally):

Output of docker version:

Client:
 Version:	18.03.0-ce
 API version:	1.37
 Go version:	go1.9.4
 Git commit:	0520e24
 Built:	Wed Mar 21 23:10:01 2018
 OS/Arch:	linux/amd64
 Experimental:	false
 Orchestrator:	swarm

Server:
 Engine:
  Version:	18.03.0-ce
  API version:	1.37 (minimum version 1.12)
  Go version:	go1.9.4
  Git commit:	0520e24
  Built:	Wed Mar 21 23:08:31 2018
  OS/Arch:	linux/amd64
  Experimental:	false

Output of docker info:

Containers: 11
 Running: 11
 Paused: 0
 Stopped: 0
Images: 39
Server Version: 18.03.0-ce
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: active
 NodeID: liej3h97oop7ur5kfatg49ppp
 Is Manager: true
 ClusterID: kee8axgptwa4tdk2sm7dvv970
 Managers: 1
 Nodes: 1
 Orchestration:
  Task History Retention Limit: 5
 Raft:
  Snapshot Interval: 10000
  Number of Old Snapshots to Retain: 0
  Heartbeat Tick: 1
  Election Tick: 3
 Dispatcher:
  Heartbeat Period: 5 seconds
 CA Configuration:
  Expiry Duration: 3 months
  Force Rotate: 0
 Autolock Managers: false
 Root Rotation In Progress: false
 Node Address: 172.17.254.35
 Manager Addresses:
  172.17.254.35:2377
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: cfd04396dc68220d1cecbe686a6cc3aa5ce3667c
runc version: 4fc53a81fb7c994640722ac585fa9ca548971871
init version: 949e6fa
Security Options:
 apparmor
 seccomp
  Profile: default
Kernel Version: 4.4.0-105-generic
Operating System: Ubuntu 16.04.3 LTS
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 3.859GiB
Name: iZ2ze0tktsnis7mhjiyab1Z
ID: OQTM:H2HJ:U2XT:WKLC:U4ZY:EHVI:QTXN:W4GK:QDA4:LUDJ:LFN7:WG3V
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

WARNING: No swap limit support

Additional environment details (AWS, VirtualBox, physical, etc.):
Aliyun cloud

Start with the docker stack deploy flow described in the reproduction and trace where the service name is checked before the daemon returns its DNS-name error. Determine whether validation belongs in the CLI or daemon, and clarify the intended policy for dots in service names. Done means the project has an agreed behavior and a corresponding regression check.