aboutsummaryrefslogtreecommitdiffstats
path: root/lib/session/session.go
blob: 60b7b8a1bf17fa986399ad58abc371aa072393bd (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
package session

import (
	"encoding/base64"
	"strconv"
	"time"

	"github.com/Sirupsen/logrus"
	"github.com/gin-gonic/gin"
	"github.com/googollee/go-socket.io"
	uuid "github.com/satori/go.uuid"
	"github.com/syncthing/syncthing/lib/sync"
)

const sessionCookieName = "xds-sid"
const sessionHeaderName = "XDS-SID"

const sessionMonitorTime = 10 // Time (in seconds) to schedule monitoring session tasks

const initSessionMaxAge = 10 // Initial session max age in seconds
const maxSessions = 100000   // Maximum number of sessions in sessMap map

const secureCookie = false // TODO: see https://github.com/astaxie/beego/blob/master/session/session.go#L218

// ClientSession contains the info of a user/client session
type ClientSession struct {
	ID       string
	WSID     string // only one WebSocket per client/session
	MaxAge   int64
	IOSocket *socketio.Socket

	// private
	expireAt time.Time
	useCount int64
}

// Sessions holds client sessions
type Sessions struct {
	router        *gin.Engine
	cookieMaxAge  int64
	sessMap       map[string]ClientSession
	mutex         sync.Mutex
	log           *logrus.Logger
	LogLevelSilly bool
	stop          chan struct{} // signals intentional stop
}

// NewClientSessions .
func NewClientSessions(router *gin.Engine, log *logrus.Logger, cookieMaxAge string, sillyLog bool) *Sessions {
	ckMaxAge, err := strconv.ParseInt(cookieMaxAge, 10, 0)
	if err != nil {
		ckMaxAge = 0
	}
	s := Sessions{
		router:        router,
		cookieMaxAge:  ckMaxAge,
		sessMap:       make(map[string]ClientSession),
		mutex:         sync.NewMutex(),
		log:           log,
		LogLevelSilly: sillyLog,
		stop:          make(chan struct{}),
	}
	s.router.Use(s.Middleware())

	// Start monitoring of sessions Map (use to manage expiration and cleanup)
	go s.monitorSessMap()

	return &s
}

// Stop sessions management
func (s *Sessions) Stop() {
	close(s.stop)
}

// Middleware is used to managed session
func (s *Sessions) Middleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		// FIXME Add CSRF management

		// Get session
		sess := s.Get(c)
		if sess == nil {
			// Allocate a new session key and put in cookie
			sess = s.newSession("")
		} else {
			s.refresh(sess.ID)
		}

		// Set session in cookie and in header
		// Do not set Domain to localhost (http://stackoverflow.com/questions/1134290/cookies-on-localhost-with-explicit-domain)
		c.SetCookie(sessionCookieName, sess.ID, int(sess.MaxAge), "/", "",
			secureCookie, false)
		c.Header(sessionHeaderName, sess.ID)

		// Save session id in gin metadata
		c.Set(sessionCookieName, sess.ID)

		c.Next()
	}
}

// Get returns the client session for a specific ID
func (s *Sessions) Get(c *gin.Context) *ClientSession {
	var sid string

	// First get from gin metadata
	v, exist := c.Get(sessionCookieName)
	if v != nil {
		sid = v.(string)
	}

	// Then look in cookie
	if !exist || sid == "" {
		sid, _ = c.Cookie(sessionCookieName)
	}

	// Then look in Header
	if sid == "" {
		sid = c.Request.Header.Get(sessionCookieName)
	}
	if sid != "" {
		s.mutex.Lock()
		defer s.mutex.Unlock()
		if key, ok := s.sessMap[sid]; ok {
			// TODO: return a copy ???
			return &key
		}
	}
	return nil
}

// IOSocketGet Get socketio definition from sid
func (s *Sessions) IOSocketGet(sid string) *socketio.Socket {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	sess, ok := s.sessMap[sid]
	if ok {
		return sess.IOSocket
	}
	return nil
}

// UpdateIOSocket updates the IO Socket definition for of a session
func (s *Sessions) UpdateIOSocket(sid string, so *socketio.Socket) error {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	if _, ok := s.sessMap[sid]; ok {
		sess := s.sessMap[sid]
		if so == nil {
			// Could be the case when socketio is closed/disconnected
			sess.WSID = ""
		} else {
			sess.WSID = (*so).Id()
		}
		sess.IOSocket = so
		s.sessMap[sid] = sess
	}
	return nil
}

// nesSession Allocate a new client session
func (s *Sessions) newSession(prefix string) *ClientSession {
	uuid := prefix + uuid.NewV4().String()
	id := base64.URLEncoding.EncodeToString([]byte(uuid))
	se := ClientSession{
		ID:       id,
		WSID:     "",
		MaxAge:   initSessionMaxAge,
		IOSocket: nil,
		expireAt: time.Now().Add(time.Duration(initSessionMaxAge) * time.Second),
		useCount: 0,
	}
	s.mutex.Lock()
	defer s.mutex.Unlock()

	s.sessMap[se.ID] = se

	s.log.Debugf("NEW session (%d): %s", len(s.sessMap), id)
	return &se
}

// refresh Move this session ID to the head of the list
func (s *Sessions) refresh(sid string) {
	s.mutex.Lock()
	defer s.mutex.Unlock()

	sess := s.sessMap[sid]
	sess.useCount++
	if sess.MaxAge < s.cookieMaxAge && sess.useCount > 1 {
		sess.MaxAge = s.cookieMaxAge
		sess.expireAt = time.Now().Add(time.Duration(sess.MaxAge) * time.Second)
	}

	// TODO - Add flood detection (like limit_req of nginx)
	// (delayed request when to much requests in a short period of time)

	s.sessMap[sid] = sess
}

func (s *Sessions) monitorSessMap() {
	for {
		select {
		case <-s.stop:
			s.log.Debugln("Stop monitorSessMap")
			return
		case <-time.After(sessionMonitorTime * time.Second):
			if s.LogLevelSilly {
				s.log.Debugf("Sessions Map size: %d", len(s.sessMap))
				s.log.Debugf("Sessions Map : %v", s.sessMap)
			}

			if len(s.sessMap) > maxSessions {
				s.log.Errorln("TOO MUCH sessions, cleanup old ones !")
			}

			s.mutex.Lock()
			for _, ss := range s.sessMap {
				if ss.expireAt.Sub(time.Now()) < 0 {
					s.log.Debugf("Delete expired session id: %s", ss.ID)
					delete(s.sessMap, ss.ID)
				}
			}
			s.mutex.Unlock()
		}
	}
}