forked from rkt/rkt
/
bridge.go
250 lines (209 loc) · 6.1 KB
/
bridge.go
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
// Copyright 2014 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"encoding/json"
"errors"
"fmt"
"net"
"os"
"runtime"
"syscall"
"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/cni/pkg/ip"
"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/cni/pkg/ipam"
"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/cni/pkg/ns"
"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/cni/pkg/skel"
"github.com/coreos/rkt/Godeps/_workspace/src/github.com/appc/cni/pkg/types"
"github.com/coreos/rkt/Godeps/_workspace/src/github.com/vishvananda/netlink"
)
const defaultBrName = "cni0"
type NetConf struct {
types.NetConf
BrName string `json:"bridge"`
IsGW bool `json:"isGateway"`
IPMasq bool `json:"ipMasq"`
MTU int `json:"mtu"`
}
func init() {
// this ensures that main runs only on main thread (thread group leader).
// since namespace ops (unshare, setns) are done for a single thread, we
// must ensure that the goroutine does not jump from OS thread to thread
runtime.LockOSThread()
}
func loadNetConf(bytes []byte) (*NetConf, error) {
n := &NetConf{
BrName: defaultBrName,
}
if err := json.Unmarshal(bytes, n); err != nil {
return nil, fmt.Errorf("failed to load netconf: %v", err)
}
return n, nil
}
func ensureBridgeAddr(br *netlink.Bridge, ipn *net.IPNet) error {
addrs, err := netlink.AddrList(br, syscall.AF_INET)
if err != nil && err != syscall.ENOENT {
return fmt.Errorf("could not get list of IP addresses: %v", err)
}
// if there're no addresses on the bridge, it's ok -- we'll add one
if len(addrs) > 0 {
ipnStr := ipn.String()
for _, a := range addrs {
// string comp is actually easiest for doing IPNet comps
if a.IPNet.String() == ipnStr {
return nil
}
}
return fmt.Errorf("%q already has an IP address different from %v", br.Name, ipn.String())
}
addr := &netlink.Addr{IPNet: ipn, Label: ""}
if err := netlink.AddrAdd(br, addr); err != nil {
return fmt.Errorf("could not add IP address to %q: %v", br.Name, err)
}
return nil
}
func bridgeByName(name string) (*netlink.Bridge, error) {
l, err := netlink.LinkByName(name)
if err != nil {
return nil, fmt.Errorf("could not lookup %q: %v", name, err)
}
br, ok := l.(*netlink.Bridge)
if !ok {
return nil, fmt.Errorf("%q already exists but is not a bridge", name)
}
return br, nil
}
func ensureBridge(brName string, mtu int) (*netlink.Bridge, error) {
br := &netlink.Bridge{
LinkAttrs: netlink.LinkAttrs{
Name: brName,
MTU: mtu,
},
}
if err := netlink.LinkAdd(br); err != nil {
if err != syscall.EEXIST {
return nil, fmt.Errorf("could not add %q: %v", brName, err)
}
// it's ok if the device already exists as long as config is similar
br, err = bridgeByName(brName)
if err != nil {
return nil, err
}
}
if err := netlink.LinkSetUp(br); err != nil {
return nil, err
}
return br, nil
}
func setupVeth(netns string, br *netlink.Bridge, ifName string, mtu int) error {
var hostVethName string
err := ns.WithNetNSPath(netns, false, func(hostNS *os.File) error {
// create the veth pair in the container and move host end into host netns
hostVeth, _, err := ip.SetupVeth(ifName, mtu, hostNS)
if err != nil {
return err
}
hostVethName = hostVeth.Attrs().Name
return nil
})
if err != nil {
return err
}
// need to lookup hostVeth again as its index has changed during ns move
hostVeth, err := netlink.LinkByName(hostVethName)
if err != nil {
return fmt.Errorf("failed to lookup %q: %v", hostVethName, err)
}
// connect host veth end to the bridge
if err = netlink.LinkSetMaster(hostVeth, br); err != nil {
return fmt.Errorf("failed to connect %q to bridge %v: %v", hostVethName, br.Attrs().Name, err)
}
return nil
}
func calcGatewayIP(ipn *net.IPNet) net.IP {
nid := ipn.IP.Mask(ipn.Mask)
return ip.NextIP(nid)
}
func setupBridge(n *NetConf) (*netlink.Bridge, error) {
// create bridge if necessary
br, err := ensureBridge(n.BrName, n.MTU)
if err != nil {
return nil, fmt.Errorf("failed to create bridge %q: %v", n.BrName, err)
}
return br, nil
}
func cmdAdd(args *skel.CmdArgs) error {
n, err := loadNetConf(args.StdinData)
if err != nil {
return err
}
br, err := setupBridge(n)
if err != nil {
return err
}
if err = setupVeth(args.Netns, br, args.IfName, n.MTU); err != nil {
return err
}
// run the IPAM plugin and get back the config to apply
result, err := ipam.ExecAdd(n.IPAM.Type, args.StdinData)
if err != nil {
return err
}
if result.IP4 == nil {
return errors.New("IPAM plugin returned missing IPv4 config")
}
if result.IP4.Gateway == nil && n.IsGW {
result.IP4.Gateway = calcGatewayIP(&result.IP4.IP)
}
err = ns.WithNetNSPath(args.Netns, false, func(hostNS *os.File) error {
return ipam.ConfigureIface(args.IfName, result)
})
if err != nil {
return err
}
if n.IsGW {
gwn := &net.IPNet{
IP: result.IP4.Gateway,
Mask: result.IP4.IP.Mask,
}
if err = ensureBridgeAddr(br, gwn); err != nil {
return err
}
if err := ip.EnableIP4Forward(); err != nil {
return fmt.Errorf("failed to enable forwarding: %v", err)
}
}
if n.IPMasq {
chain := "CNI-" + n.Name
if err = ip.SetupIPMasq(ip.Network(&result.IP4.IP), chain); err != nil {
return err
}
}
return result.Print()
}
func cmdDel(args *skel.CmdArgs) error {
n, err := loadNetConf(args.StdinData)
if err != nil {
return err
}
err = ipam.ExecDel(n.IPAM.Type, args.StdinData)
if err != nil {
return err
}
return ns.WithNetNSPath(args.Netns, false, func(hostNS *os.File) error {
return ip.DelLinkByName(args.IfName)
})
}
func main() {
skel.PluginMain(cmdAdd, cmdDel)
}