-
Notifications
You must be signed in to change notification settings - Fork 51
/
portset.go
282 lines (219 loc) · 7.28 KB
/
portset.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
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
package portset
import (
"errors"
"fmt"
"io/ioutil"
"os/user"
"strconv"
"strings"
"time"
"github.com/aporeto-inc/go-ipset/ipset"
"go.aporeto.io/trireme-lib/utils/cache"
"go.aporeto.io/trireme-lib/utils/portcache"
"go.uber.org/zap"
)
const (
procNetTCPFile = "/proc/net/tcp"
portSetUpdateIntervalinSeconds = 2
portEntryTimeout = 5 * portSetUpdateIntervalinSeconds
uidFieldOffset = 7
procHeaderLineNum = 0
portOffset = 1
ipPortOffset = 1
sockStateOffset = 3
sockListeningState = "0A"
hexFormat = 16
integerSize = 64
minimumFields = 2
)
// portSetInstance contains look up tables to manage updates to ipset portsets.
type portSetInstance struct {
userPortSet cache.DataStore
userPortMap cache.DataStore
markUserMap cache.DataStore
contextIDFromTCPPort *portcache.PortCache
}
// expirer deletes the port entry in the portset when the key uid:port expires.
func expirer(c cache.DataStore, id interface{}, item interface{}) {
userPort := strings.Split(id.(string), ":")
portSetObject := item.(*portSetInstance)
if len(userPort) < minimumFields {
zap.L().Debug("Failed to remove key from the cache")
return
}
if portSetObject == nil {
zap.L().Debug("Invalid portSetObject")
return
}
user := userPort[0]
port := userPort[1]
if err := portSetObject.deletePortSet(user, port); err != nil {
zap.L().Debug("Cache: Failed to delete port from set", zap.Error(err))
}
// delete the port from contextIDFromTCPPort cache
if err := portSetObject.contextIDFromTCPPort.RemoveStringPorts(port); err != nil {
zap.L().Debug("Unable to remove port from contextIDFromTCPPort Cache")
}
}
// New creates an implementation portset interface.
func New(contextIDFromTCPPort *portcache.PortCache) PortSet {
p := &portSetInstance{
userPortSet: cache.NewCache("userPortSet"),
userPortMap: cache.NewCacheWithExpirationNotifier("userPortMap", portEntryTimeout*time.Second, expirer),
markUserMap: cache.NewCache("markUserMap"),
contextIDFromTCPPort: contextIDFromTCPPort,
}
go startPortSetTask(p)
return p
}
func getUserName(uid string) (string, error) {
u, err := user.LookupId(uid)
if err != nil {
return "", err
}
return u.Username, nil
}
// AddPortToUser adds/updates userPortMap cache. returns true if user key is already present.
func (p *portSetInstance) AddPortToUser(userName string, port string) (bool, error) {
key := userName + ":" + port
updated := p.userPortMap.AddOrUpdate(key, p)
// program the ipset
if err := p.addPortSet(userName, port); err != nil {
return false, err
}
return updated, nil
}
// AddUserPortSet adds/updates userPortSet/markUserMap cache. userPortSet cache
// maps user to the portset associated with its PU. markUserMap maps the packet mark
// the userName. This gets called during the creation of PU/on reception of application SYN-ACK packet.
func (p *portSetInstance) AddUserPortSet(userName string, portset string, mark string) (err error) {
p.userPortSet.AddOrUpdate(userName, portset)
p.markUserMap.AddOrUpdate(mark, userName)
return nil
}
// getUserPortSet returns the portset associated with user.
func (p *portSetInstance) getUserPortSet(userName string) (string, error) {
portSetName, err := p.userPortSet.Get(userName)
if err != nil {
return "", fmt.Errorf("invalid portset name: %s", err)
}
port, ok := portSetName.(string)
if !ok {
return "", errors.New("invalid portset name: portset name is not a string")
}
return port, nil
}
// DelUserPortSet deletes user and mark entries from caches.
func (p *portSetInstance) DelUserPortSet(userName string, mark string) (err error) {
if err = p.userPortSet.Remove(userName); err != nil {
return fmt.Errorf("unable to remove uid from portset cache: %s", err)
}
return p.markUserMap.Remove(mark)
}
// GetuserMark return username associated with packet mark.
func (p *portSetInstance) GetUserMark(mark string) (string, error) {
userName, err := p.markUserMap.Get(mark)
if err != nil {
return "", fmt.Errorf("invalid mark: %s", err)
}
user, ok := userName.(string)
if !ok {
return "", errors.New("invalid mark: not a string")
}
return user, nil
}
// addPortSet programs the ipset portset with port. The portset name is derived from userPortSet cache.
func (p *portSetInstance) addPortSet(userName string, port string) (err error) {
puPortSetName, err := p.getUserPortSet(userName)
if err != nil {
return fmt.Errorf("unable to get portset from uid: %s", err)
}
ips := ipset.IPSet{
Name: puPortSetName,
}
if _, err = strconv.Atoi(port); err != nil {
return fmt.Errorf("invalid port: %s", err)
}
if err = ips.Add(port, 0); err != nil {
return fmt.Errorf("unable to add port to set: %s", err)
}
return nil
}
// deletePortSet deletes the portset.
func (p *portSetInstance) deletePortSet(userName string, port string) error {
puPortSetName, err := p.getUserPortSet(userName)
if err != nil {
return fmt.Errorf("unable to get portset from uid: %s", err)
}
ips := ipset.IPSet{
Name: puPortSetName,
}
if _, err = strconv.Atoi(port); err != nil {
return fmt.Errorf("invalid port: %s", err)
}
if err = ips.Del(port); err != nil {
return fmt.Errorf("unable to delete port from portset: %s", err)
}
return nil
}
// startPortSetTask is a go routine that periodically scans /proc/net/tcp file
// for listening ports and programs the portsets. This worker thread is setup
// during datapath initilisation.
func startPortSetTask(p *portSetInstance) {
t := time.NewTicker(portSetUpdateIntervalinSeconds * time.Second)
for range t.C {
// Update PortSet periodically.
p.updateIPPortSets()
}
}
func (p *portSetInstance) updateIPPortSets() {
buffer, err := ioutil.ReadFile(procNetTCPFile)
if err != nil {
zap.L().Debug("Failed to read /proc/net/tcp file", zap.Error(err))
// This is a go routine, cannot return error
return
}
s := string(buffer)
for cnt, line := range strings.Split(s, "\n") {
line := strings.Fields(line)
// continue if not a valid line
if len(line) < uidFieldOffset {
continue
}
if (cnt == procHeaderLineNum) || (line[sockStateOffset] != sockListeningState) {
continue
}
uid := line[uidFieldOffset]
ipPort := strings.Split(line[ipPortOffset], ":")
if len(ipPort) < minimumFields {
zap.L().Debug("Failed to extract port")
continue
}
port := ipPort[portOffset]
// convert the hex port to int
portNum, err := strconv.ParseInt(port, hexFormat, integerSize)
if err != nil {
zap.L().Debug("Failed to convert port to Int", zap.Error(err))
continue
}
// /proc/net/tcp file contains uid. Conversion to
// userName is required as they are keys to lookup tables.
userName, err := getUserName(uid)
if err != nil {
zap.L().Debug("Error converting to username", zap.Error(err))
continue
}
port = strconv.Itoa(int(portNum))
portKey := userName + ":" + port
// check if username corresponds to a valid uidloginpu
if _, err = p.userPortSet.Get(userName); err != nil {
continue
}
if updated := p.userPortMap.AddOrUpdate(portKey, p); updated {
continue
}
if err = p.addPortSet(userName, port); err != nil {
zap.L().Debug("Unable to add port to portset ", zap.Error(err))
}
}
}