summaryrefslogtreecommitdiffstats
path: root/multi.c
blob: 5f70b6f3d1eaa29ec68f9e78273c1a91f1bbc489 (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
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
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single TCP/UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2008 Telethra, Inc. <sales@openvpn.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "syshead.h"

#if P2MP_SERVER

#include "multi.h"
#include "push.h"
#include "misc.h"
#include "otime.h"
#include "gremlin.h"

#include "memdbg.h"

#include "forward-inline.h"
#include "pf-inline.h"

/*#define MULTI_DEBUG_EVENT_LOOP*/

#ifdef MULTI_DEBUG_EVENT_LOOP
static const char *
id (struct multi_instance *mi)
{
  if (mi)
    return tls_common_name (mi->context.c2.tls_multi, false);
  else
    return "NULL";
}
#endif

#ifdef MANAGEMENT_DEF_AUTH
static void
set_cc_config (struct multi_instance *mi, struct buffer_list *cc_config)
{
  if (mi->cc_config)
    buffer_list_free (mi->cc_config);
  mi->cc_config = cc_config;
}
#endif

static bool
learn_address_script (const struct multi_context *m,
		      const struct multi_instance *mi,
		      const char *op,
		      const struct mroute_addr *addr)
{
  struct gc_arena gc = gc_new ();
  struct env_set *es;
  bool ret = true;
  struct plugin_list *plugins;

  /* get environmental variable source */
  if (mi && mi->context.c2.es)
    es = mi->context.c2.es;
  else
    es = env_set_create (&gc);

  /* get plugin source */
  if (mi)
    plugins = mi->context.plugins;
  else
    plugins = m->top.plugins;

  if (plugin_defined (plugins, OPENVPN_PLUGIN_LEARN_ADDRESS))
    {
      struct argv argv = argv_new ();
      argv_printf (&argv, "%s %s",
		   op,
		   mroute_addr_print (addr, &gc));
      if (mi)
	argv_printf_cat (&argv, "%s", tls_common_name (mi->context.c2.tls_multi, false));
      if (plugin_call (plugins, OPENVPN_PLUGIN_LEARN_ADDRESS, &argv, NULL, es) != OPENVPN_PLUGIN_FUNC_SUCCESS)
	{
	  msg (M_WARN, "WARNING: learn-address plugin call failed");
	  ret = false;
	}
      argv_reset (&argv);
    }

  if (m->top.options.learn_address_script)
    {
      struct argv argv = argv_new ();
      setenv_str (es, "script_type", "learn-address");
      argv_printf (&argv, "%s %s %s",
		   m->top.options.learn_address_script,
		   op,
		   mroute_addr_print (addr, &gc));
      if (mi)
	argv_printf_cat (&argv, "%s", tls_common_name (mi->context.c2.tls_multi, false));
      if (!openvpn_execve_check (&argv, es, S_SCRIPT, "WARNING: learn-address command failed"))
	ret = false;
      argv_reset (&argv);
    }

  gc_free (&gc);
  return ret;
}

void
multi_ifconfig_pool_persist (struct multi_context *m, bool force)
{
 /* write pool data to file */
  if (m->ifconfig_pool
      && m->top.c1.ifconfig_pool_persist
      && (force || ifconfig_pool_write_trigger (m->top.c1.ifconfig_pool_persist)))
    {
      ifconfig_pool_write (m->top.c1.ifconfig_pool_persist, m->ifconfig_pool);
    }
}

static void
multi_reap_range (const struct multi_context *m,
		  int start_bucket,
		  int end_bucket)
{
  struct gc_arena gc = gc_new ();
  struct hash_iterator hi;
  struct hash_element *he;

  if (start_bucket < 0)
    {
      start_bucket = 0;
      end_bucket = hash_n_buckets (m->vhash);
    }

  dmsg (D_MULTI_DEBUG, "MULTI: REAP range %d -> %d", start_bucket, end_bucket);
  hash_iterator_init_range (m->vhash, &hi, true, start_bucket, end_bucket);
  while ((he = hash_iterator_next (&hi)) != NULL)
    {
      struct multi_route *r = (struct multi_route *) he->value;
      if (!multi_route_defined (m, r))
	{
	  dmsg (D_MULTI_DEBUG, "MULTI: REAP DEL %s",
	       mroute_addr_print (&r->addr, &gc));
	  learn_address_script (m, NULL, "delete", &r->addr);
	  multi_route_del (r);
	  hash_iterator_delete_element (&hi);
	}
    }
  hash_iterator_free (&hi);
  gc_free (&gc);
}

static void
multi_reap_all (const struct multi_context *m)
{
  multi_reap_range (m, -1, 0);
}

static struct multi_reap *
multi_reap_new (int buckets_per_pass)
{
  struct multi_reap *mr;
  ALLOC_OBJ (mr, struct multi_reap);
  mr->bucket_base = 0;
  mr->buckets_per_pass = buckets_per_pass;
  mr->last_call = now;
  return mr;
}

void
multi_reap_process_dowork (const struct multi_context *m)
{
  struct multi_reap *mr = m->reaper;
  if (mr->bucket_base >= hash_n_buckets (m->vhash))
    mr->bucket_base = 0;
  multi_reap_range (m, mr->bucket_base, mr->bucket_base + mr->buckets_per_pass); 
  mr->bucket_base += mr->buckets_per_pass;
  mr->last_call = now;
}

static void
multi_reap_free (struct multi_reap *mr)
{
  free (mr);
}

/*
 * How many buckets in vhash to reap per pass.
 */
static int
reap_buckets_per_pass (int n_buckets)
{
  return constrain_int (n_buckets / REAP_DIVISOR, REAP_MIN, REAP_MAX);
}

#ifdef MANAGEMENT_DEF_AUTH

static uint32_t
cid_hash_function (const void *key, uint32_t iv)
{
  const unsigned long *k = (const unsigned long *)key;
  return (uint32_t) *k;
}

static bool
cid_compare_function (const void *key1, const void *key2)
{
  const unsigned long *k1 = (const unsigned long *)key1;
  const unsigned long *k2 = (const unsigned long *)key2;
  return *k1 == *k2;
}

#endif

/*
 * Main initialization function, init multi_context object.
 */
void
multi_init (struct multi_context *m, struct context *t, bool tcp_mode, int thread_mode)
{
  int dev = DEV_TYPE_UNDEF;

  msg (D_MULTI_LOW, "MULTI: multi_init called, r=%d v=%d",
       t->options.real_hash_size,
       t->options.virtual_hash_size);

  /*
   * Get tun/tap/null device type
   */
  dev = dev_type_enum (t->options.dev, t->options.dev_type);

  /*
   * Init our multi_context object.
   */
  CLEAR (*m);
  
  m->thread_mode = thread_mode;

  /*
   * Real address hash table (source port number is
   * considered to be part of the address).  Used
   * to determine which client sent an incoming packet
   * which is seen on the TCP/UDP socket.
   */
  m->hash = hash_init (t->options.real_hash_size,
		       get_random (),
		       mroute_addr_hash_function,
		       mroute_addr_compare_function);

  /*
   * Virtual address hash table.  Used to determine
   * which client to route a packet to. 
   */
  m->vhash = hash_init (t->options.virtual_hash_size,
			get_random (),
			mroute_addr_hash_function,
			mroute_addr_compare_function);

  /*
   * This hash table is a clone of m->hash but with a
   * bucket size of one so that it can be used
   * for fast iteration through the list.
   */
  m->iter = hash_init (1,
		       get_random (),
		       mroute_addr_hash_function,
		       mroute_addr_compare_function);

#ifdef MANAGEMENT_DEF_AUTH
  m->cid_hash = hash_init (t->options.real_hash_size,
			   0,
			   cid_hash_function,
			   cid_compare_function);
#endif

  /*
   * This is our scheduler, for time-based wakeup
   * events.
   */
  m->schedule = schedule_init ();

  /*
   * Limit frequency of incoming connections to control
   * DoS.
   */
  m->new_connection_limiter = frequency_limit_init (t->options.cf_max,
						    t->options.cf_per);

  /*
   * Allocate broadcast/multicast buffer list
   */
  m->mbuf = mbuf_init (t->options.n_bcast_buf);

  /*
   * Different status file format options are available
   */
  m->status_file_version = t->options.status_file_version;

  /*
   * Possibly allocate an ifconfig pool, do it
   * differently based on whether a tun or tap style
   * tunnel.
   */
  if (t->options.ifconfig_pool_defined)
    {
      if (dev == DEV_TYPE_TAP)
	{
	  m->ifconfig_pool = ifconfig_pool_init (IFCONFIG_POOL_INDIV,
						 t->options.ifconfig_pool_start,
						 t->options.ifconfig_pool_end,
						 t->options.duplicate_cn);
	}
      else if (dev == DEV_TYPE_TUN)
	{
	  m->ifconfig_pool = ifconfig_pool_init (
	    (t->options.topology == TOP_NET30) ? IFCONFIG_POOL_30NET : IFCONFIG_POOL_INDIV,
	    t->options.ifconfig_pool_start,
	    t->options.ifconfig_pool_end,
	    t->options.duplicate_cn);
	}
      else
	{
	  ASSERT (0);
	}

      /* reload pool data from file */
      if (t->c1.ifconfig_pool_persist)
	ifconfig_pool_read (t->c1.ifconfig_pool_persist, m->ifconfig_pool);
    }

  /*
   * Help us keep track of routing table.
   */
  m->route_helper = mroute_helper_init (MULTI_CACHE_ROUTE_TTL);

  /*
   * Initialize route and instance reaper.
   */
  m->reaper = multi_reap_new (reap_buckets_per_pass (t->options.virtual_hash_size));

  /*
   * Get local ifconfig address
   */
  CLEAR (m->local);
  ASSERT (t->c1.tuntap);
  mroute_extract_in_addr_t (&m->local, t->c1.tuntap->local);

  /*
   * Per-client limits
   */
  m->max_clients = t->options.max_clients;

  /*
   * Initialize multi-socket TCP I/O wait object
   */
  if (tcp_mode)
    m->mtcp = multi_tcp_init (t->options.max_clients, &m->max_clients);
  m->tcp_queue_limit = t->options.tcp_queue_limit;
  
  /*
   * Allow client <-> client communication, without going through
   * tun/tap interface and network stack?
   */
  m->enable_c2c = t->options.enable_c2c;
}

const char *
multi_instance_string (const struct multi_instance *mi, bool null, struct gc_arena *gc)
{
  if (mi)
    {
      struct buffer out = alloc_buf_gc (256, gc);
      const char *cn = tls_common_name (mi->context.c2.tls_multi, true);

      if (cn)
	buf_printf (&out, "%s/", cn);
      buf_printf (&out, "%s", mroute_addr_print (&mi->real, gc));
      return BSTR (&out);
    }
  else if (null)
    return NULL;
  else
    return "UNDEF";
}

void
generate_prefix (struct multi_instance *mi)
{
  mi->msg_prefix = multi_instance_string (mi, true, &mi->gc);
  set_prefix (mi);
}

void
ungenerate_prefix (struct multi_instance *mi)
{
  mi->msg_prefix = NULL;
  set_prefix (mi);
}

static const char *
mi_prefix (const struct multi_instance *mi)
{
  if (mi && mi->msg_prefix)
    return mi->msg_prefix;
  else
    return "UNDEF_I";
}

/*
 * Tell the route helper about deleted iroutes so
 * that it can update its mask of currently used
 * CIDR netlengths.
 */
static void
multi_del_iroutes (struct multi_context *m,
		   struct multi_instance *mi)
{
  const struct iroute *ir;
  if (TUNNEL_TYPE (mi->context.c1.tuntap) == DEV_TYPE_TUN)
    {
      for (ir = mi->context.options.iroutes; ir != NULL; ir = ir->next)
	mroute_helper_del_iroute (m->route_helper, ir);
    }
}

static void
multi_client_disconnect_setenv (struct multi_context *m,
				struct multi_instance *mi)
{
  /* setenv client real IP address */
  setenv_trusted (mi->context.c2.es, get_link_socket_info (&mi->context));

  /* setenv stats */
  setenv_counter (mi->context.c2.es, "bytes_received", mi->context.c2.link_read_bytes);
  setenv_counter (mi->context.c2.es, "bytes_sent", mi->context.c2.link_write_bytes);

  /* setenv connection duration */
  {
    const unsigned int duration = (unsigned int) now - mi->created;
    setenv_unsigned (mi->context.c2.es, "time_duration", duration);
  }
}

static void
multi_client_disconnect_script (struct multi_context *m,
				struct multi_instance *mi)
{
  if ((mi->context.c2.context_auth == CAS_SUCCEEDED && mi->connection_established_flag)
      || mi->context.c2.context_auth == CAS_PARTIAL)
    {
      multi_client_disconnect_setenv (m, mi);

      if (plugin_defined (mi->context.plugins, OPENVPN_PLUGIN_CLIENT_DISCONNECT))
	{
	  if (plugin_call (mi->context.plugins, OPENVPN_PLUGIN_CLIENT_DISCONNECT, NULL, NULL, mi->context.c2.es) != OPENVPN_PLUGIN_FUNC_SUCCESS)
	    msg (M_WARN, "WARNING: client-disconnect plugin call failed");
	}

      if (mi->context.options.client_disconnect_script)
	{
	  struct argv argv = argv_new ();
	  setenv_str (mi->context.c2.es, "script_type", "client-disconnect");
	  argv_printf (&argv, "%s", mi->context.options.client_disconnect_script);
	  openvpn_execve_check (&argv, mi->context.c2.es, S_SCRIPT, "client-disconnect command failed");
	  argv_reset (&argv);
	}
#ifdef MANAGEMENT_DEF_AUTH
      if (management)
	management_notify_client_close (management, &mi->context.c2.mda_context, mi->context.c2.es);
#endif

    }
}

void
multi_close_instance (struct multi_context *m,
		      struct multi_instance *mi,
		      bool shutdown)
{
  perf_push (PERF_MULTI_CLOSE_INSTANCE);

  ASSERT (!mi->halt);
  mi->halt = true;

  dmsg (D_MULTI_DEBUG, "MULTI: multi_close_instance called");

  /* prevent dangling pointers */
  if (m->pending == mi)
    multi_set_pending (m, NULL);
  if (m->earliest_wakeup == mi)
    m->earliest_wakeup = NULL;

  if (!shutdown)
    {
      if (mi->did_real_hash)
	{
	  ASSERT (hash_remove (m->hash, &mi->real));
	}
      if (mi->did_iter)
	{
	  ASSERT (hash_remove (m->iter, &mi->real));
	}
#ifdef MANAGEMENT_DEF_AUTH
      if (mi->did_cid_hash)
	{
	  ASSERT (hash_remove (m->cid_hash, &mi->context.c2.mda_context.cid));
	}
#endif

      schedule_remove_entry (m->schedule, (struct schedule_entry *) mi);

      ifconfig_pool_release (m->ifconfig_pool, mi->vaddr_handle, false);
      
      if (mi->did_iroutes)
        {
          multi_del_iroutes (m, mi);
          mi->did_iroutes = false;
        }

      if (m->mtcp)
	multi_tcp_dereference_instance (m->mtcp, mi);

      mbuf_dereference_instance (m->mbuf, mi);
    }

#ifdef MANAGEMENT_DEF_AUTH
  set_cc_config (mi, NULL);
#endif

  multi_client_disconnect_script (m, mi);

  if (mi->did_open_context)
    close_context (&mi->context, SIGTERM, CC_GC_FREE);

  multi_tcp_instance_specific_free (mi);

  ungenerate_prefix (mi);

  /*
   * Don't actually delete the instance memory allocation yet,
   * because virtual routes may still point to it.  Let the
   * vhash reaper deal with it.
   */
  multi_instance_dec_refcount (mi);

  perf_pop ();
}

/*
 * Called on shutdown or restart.
 */
void
multi_uninit (struct multi_context *m)
{
  if (m->thread_mode & MC_WORK_THREAD)
    {
      multi_top_free (m);
      m->thread_mode = MC_UNDEF;
    }
  else if (m->thread_mode)
    {
      if (m->hash)
	{
	  struct hash_iterator hi;
	  struct hash_element *he;

	  hash_iterator_init (m->iter, &hi, true);
	  while ((he = hash_iterator_next (&hi)))
	    {
	      struct multi_instance *mi = (struct multi_instance *) he->value;
	      mi->did_iter = false;
	      multi_close_instance (m, mi, true);
	    }
	  hash_iterator_free (&hi);

	  multi_reap_all (m);

	  hash_free (m->hash);
	  hash_free (m->vhash);
	  hash_free (m->iter);
#ifdef MANAGEMENT_DEF_AUTH
	  hash_free (m->cid_hash);
#endif
	  m->hash = NULL;

	  schedule_free (m->schedule);
	  mbuf_free (m->mbuf);
	  ifconfig_pool_free (m->ifconfig_pool);
	  frequency_limit_free (m->new_connection_limiter);
	  multi_reap_free (m->reaper);
	  mroute_helper_free (m->route_helper);
	  multi_tcp_free (m->mtcp);
	  m->thread_mode = MC_UNDEF;
	}
    }
}

/*
 * Create a client instance object for a newly connected client.
 */
struct multi_instance *
multi_create_instance (struct multi_context *m, const struct mroute_addr *real)
{
  struct gc_arena gc = gc_new ();
  struct multi_instance *mi;

  perf_push (PERF_MULTI_CREATE_INSTANCE);

  msg (D_MULTI_LOW, "MULTI: multi_create_instance called");

  ALLOC_OBJ_CLEAR (mi, struct multi_instance);

  mutex_init (&mi->mutex);
  mi->gc = gc_new ();
  multi_instance_inc_refcount (mi);
  mi->vaddr_handle = -1;
  mi->created = now;
  mroute_addr_init (&mi->real);

  if (real)
    {
      mi->real = *real;
      generate_prefix (mi);
    }

  mi->did_open_context = true;
  inherit_context_child (&mi->context, &m->top);
  if (IS_SIG (&mi->context))
    goto err;

  mi->context.c2.context_auth = CAS_PENDING;

  if (hash_n_elements (m->hash) >= m->max_clients)
    {
      msg (D_MULTI_ERRORS, "MULTI: new incoming connection would exceed maximum number of clients (%d)", m->max_clients);
      goto err;
    }

  if (!real) /* TCP mode? */
    {
      if (!multi_tcp_instance_specific_init (m, mi))
	goto err;
      generate_prefix (mi);
    }

  if (!hash_add (m->iter, &mi->real, mi, false))
    {
      msg (D_MULTI_LOW, "MULTI: unable to add real address [%s] to iterator hash table",
	   mroute_addr_print (&mi->real, &gc));
      goto err;
    }
  mi->did_iter = true;

#ifdef MANAGEMENT_DEF_AUTH
  do {
    mi->context.c2.mda_context.cid = m->cid_counter++;
  } while (!hash_add (m->cid_hash, &mi->context.c2.mda_context.cid, mi, false));
  mi->did_cid_hash = true;
#endif

  mi->context.c2.push_reply_deferred = true;

  if (!multi_process_post (m, mi, MPP_PRE_SELECT))
    {
      msg (D_MULTI_ERRORS, "MULTI: signal occurred during client instance initialization");
      goto err;
    }

  perf_pop ();
  gc_free (&gc);
  return mi;

 err:
  multi_close_instance (m, mi, false);
  perf_pop ();
  gc_free (&gc);
  return NULL;
}

/*
 * Dump tables -- triggered by SIGUSR2.
 * If status file is defined, write to file.
 * If status file is NULL, write to syslog.
 */
void
multi_print_status (struct multi_context *m, struct status_output *so, const int version)
{
  if (m->hash)
    {
      struct gc_arena gc_top = gc_new ();
      struct hash_iterator hi;
      const struct hash_element *he;

      status_reset (so);

      if (version == 1) /* WAS: m->status_file_version */
	{
	  /*
	   * Status file version 1
	   */
	  status_printf (so, PACKAGE_NAME " CLIENT LIST");
	  status_printf (so, "Updated,%s", time_string (0, 0, false, &gc_top));
	  status_printf (so, "Common Name,Real Address,Bytes Received,Bytes Sent,Connected Since");
	  hash_iterator_init (m->hash, &hi, true);
	  while ((he = hash_iterator_next (&hi)))
	    {
	      struct gc_arena gc = gc_new ();
	      const struct multi_instance *mi = (struct multi_instance *) he->value;

	      if (!mi->halt)
		{
		  status_printf (so, "%s,%s," counter_format "," counter_format ",%s",
				 tls_common_name (mi->context.c2.tls_multi, false),
				 mroute_addr_print (&mi->real, &gc),
				 mi->context.c2.link_read_bytes,
				 mi->context.c2.link_write_bytes,
				 time_string (mi->created, 0, false, &gc));
		}
	      gc_free (&gc);
	    }
	  hash_iterator_free (&hi);

	  status_printf (so, "ROUTING TABLE");
	  status_printf (so, "Virtual Address,Common Name,Real Address,Last Ref");
	  hash_iterator_init (m->vhash, &hi, true);
	  while ((he = hash_iterator_next (&hi)))
	    {
	      struct gc_arena gc = gc_new ();
	      const struct multi_route *route = (struct multi_route *) he->value;

	      if (multi_route_defined (m, route))
		{
		  const struct multi_instance *mi = route->instance;
		  const struct mroute_addr *ma = &route->addr;
		  char flags[2] = {0, 0};

		  if (route->flags & MULTI_ROUTE_CACHE)
		    flags[0] = 'C';
		  status_printf (so, "%s%s,%s,%s,%s",
				 mroute_addr_print (ma, &gc),
				 flags,
				 tls_common_name (mi->context.c2.tls_multi, false),
				 mroute_addr_print (&mi->real, &gc),
				 time_string (route->last_reference, 0, false, &gc));
		}
	      gc_free (&gc);
	    }
	  hash_iterator_free (&hi);

	  status_printf (so, "GLOBAL STATS");
	  if (m->mbuf)
	    status_printf (so, "Max bcast/mcast queue length,%d",
			   mbuf_maximum_queued (m->mbuf));

	  status_printf (so, "END");
	}
      else if (version == 2)
	{
	  /*
	   * Status file version 2
	   */
	  status_printf (so, "TITLE,%s", title_string);
	  status_printf (so, "TIME,%s,%u", time_string (now, 0, false, &gc_top), (unsigned int)now);
	  status_printf (so, "HEADER,CLIENT_LIST,Common Name,Real Address,Virtual Address,Bytes Received,Bytes Sent,Connected Since,Connected Since (time_t)");
	  hash_iterator_init (m->hash, &hi, true);
	  while ((he = hash_iterator_next (&hi)))
	    {
	      struct gc_arena gc = gc_new ();
	      const struct multi_instance *mi = (struct multi_instance *) he->value;

	      if (!mi->halt)
		{
		  status_printf (so, "CLIENT_LIST,%s,%s,%s," counter_format "," counter_format ",%s,%u",
				 tls_common_name (mi->context.c2.tls_multi, false),
				 mroute_addr_print (&mi->real, &gc),
				 print_in_addr_t (mi->reporting_addr, IA_EMPTY_IF_UNDEF, &gc),
				 mi->context.c2.link_read_bytes,
				 mi->context.c2.link_write_bytes,
				 time_string (mi->created, 0, false, &gc),
				 (unsigned int)mi->created);
		}
	      gc_free (&gc);
	    }
	  hash_iterator_free (&hi);

	  status_printf (so, "HEADER,ROUTING_TABLE,Virtual Address,Common Name,Real Address,Last Ref,Last Ref (time_t)");
	  hash_iterator_init (m->vhash, &hi, true);
	  while ((he = hash_iterator_next (&hi)))
	    {
	      struct gc_arena gc = gc_new ();
	      const struct multi_route *route = (struct multi_route *) he->value;

	      if (multi_route_defined (m, route))
		{
		  const struct multi_instance *mi = route->instance;
		  const struct mroute_addr *ma = &route->addr;
		  char flags[2] = {0, 0};

		  if (route->flags & MULTI_ROUTE_CACHE)
		    flags[0] = 'C';
		  status_printf (so, "ROUTING_TABLE,%s%s,%s,%s,%s,%u",
				 mroute_addr_print (ma, &gc),
				 flags,
				 tls_common_name (mi->context.c2.tls_multi, false),
				 mroute_addr_print (&mi->real, &gc),
				 time_string (route->last_reference, 0, false, &gc),
				 (unsigned int)route->last_reference);
		}
	      gc_free (&gc);
	    }
	  hash_iterator_free (&hi);

	  if (m->mbuf)
	    status_printf (so, "GLOBAL_STATS,Max bcast/mcast queue length,%d",
			   mbuf_maximum_queued (m->mbuf));

	  status_printf (so, "END");
	}
      else
	{
	  status_printf (so, "ERROR: bad status format version number");
	}

#ifdef PACKET_TRUNCATION_CHECK
      {
	status_printf (so, "HEADER,ERRORS,Common Name,TUN Read Trunc,TUN Write Trunc,Pre-encrypt Trunc,Post-decrypt Trunc");
	hash_iterator_init (m->hash, &hi, true);
	while ((he = hash_iterator_next (&hi)))
	    {
	      struct gc_arena gc = gc_new ();
	      const struct multi_instance *mi = (struct multi_instance *) he->value;

	      if (!mi->halt)
		{
		  status_printf (so, "ERRORS,%s," counter_format "," counter_format "," counter_format "," counter_format,
				 tls_common_name (mi->context.c2.tls_multi, false),
				 m->top.c2.n_trunc_tun_read,
				 mi->context.c2.n_trunc_tun_write,
				 mi->context.c2.n_trunc_pre_encrypt,
				 mi->context.c2.n_trunc_post_decrypt);
		}
	      gc_free (&gc);
	    }
	hash_iterator_free (&hi);
      }
#endif

      status_flush (so);
      gc_free (&gc_top);
    }
}

/*
 * Learn a virtual address or route.
 * The learn will fail if the learn address
 * script/plugin fails.  In this case the
 * return value may be != mi.
 * Return the instance which owns this route,
 * or NULL if none.
 */
static struct multi_instance *
multi_learn_addr (struct multi_context *m,
		  struct multi_instance *mi,
		  const struct mroute_addr *addr,
		  const unsigned int flags)
{
  struct hash_element *he;
  const uint32_t hv = hash_value (m->vhash, addr);
  struct hash_bucket *bucket = hash_bucket (m->vhash, hv);
  struct multi_route *oldroute = NULL;
  struct multi_instance *owner = NULL;

  hash_bucket_lock (bucket);

  /* if route currently exists, get the instance which owns it */
  he = hash_lookup_fast (m->vhash, bucket, addr, hv);
  if (he)
    oldroute = (struct multi_route *) he->value;
  if (oldroute && multi_route_defined (m, oldroute))
    owner = oldroute->instance;

  /* do we need to add address to hash table? */
  if ((!owner || owner != mi)
      && mroute_learnable_address (addr)
      && !mroute_addr_equal (addr, &m->local))
    {
      struct gc_arena gc = gc_new ();
      struct multi_route *newroute;
      bool learn_succeeded = false;

      ALLOC_OBJ (newroute, struct multi_route);
      newroute->addr = *addr;
      newroute->instance = mi;
      newroute->flags = flags;
      newroute->last_reference = now;
      newroute->cache_generation = 0;

      /* The cache is invalidated when cache_generation is incremented */
      if (flags & MULTI_ROUTE_CACHE)
	newroute->cache_generation = m->route_helper->cache_generation;

      if (oldroute) /* route already exists? */
	{
	  if (route_quota_test (m, mi) && learn_address_script (m, mi, "update", &newroute->addr))
	    {
	      learn_succeeded = true;
	      owner = mi;
	      multi_instance_inc_refcount (mi);
	      route_quota_inc (mi);

	      /* delete old route */
	      multi_route_del (oldroute);

	      /* modify hash table entry, replacing old route */
	      he->key = &newroute->addr;
	      he->value = newroute;
	    }
	}
      else
	{
	  if (route_quota_test (m, mi) && learn_address_script (m, mi, "add", &newroute->addr))
	    {
	      learn_succeeded = true;
	      owner = mi;
	      multi_instance_inc_refcount (mi);
	      route_quota_inc (mi);

	      /* add new route */
	      hash_add_fast (m->vhash, bucket, &newroute->addr, hv, newroute);
	    }
	}
      
      msg (D_MULTI_LOW, "MULTI: Learn%s: %s -> %s",
	   learn_succeeded ? "" : " FAILED",
	   mroute_addr_print (&newroute->addr, &gc),
	   multi_instance_string (mi, false, &gc));

      if (!learn_succeeded)
	free (newroute);

      gc_free (&gc);
    }

  hash_bucket_unlock (bucket);
  return owner;
}

/*
 * Get client instance based on virtual address.
 */
static struct multi_instance *
multi_get_instance_by_virtual_addr (struct multi_context *m,
				    const struct mroute_addr *addr,
				    bool cidr_routing)
{
  struct multi_route *route;
  struct multi_instance *ret = NULL;

  /* check for local address */
  if (mroute_addr_equal (addr, &m->local))
    return NULL;

  route = (struct multi_route *) hash_lookup (m->vhash, addr);

  /* does host route (possible cached) exist? */
  if (route && multi_route_defined (m, route))
    {
      struct multi_instance *mi = route->instance;
      route->last_reference = now;
      ret = mi;
    }
  else if (cidr_routing) /* do we need to regenerate a host route cache entry? */
    {
      struct mroute_helper *rh = m->route_helper;
      struct mroute_addr tryaddr;
      int i;

      mroute_helper_lock (rh);

      /* cycle through each CIDR length */
      for (i = 0; i < rh->n_net_len; ++i)
	{
	  tryaddr = *addr;
	  tryaddr.type |= MR_WITH_NETBITS;
	  tryaddr.netbits = rh->net_len[i];
	  mroute_addr_mask_host_bits (&tryaddr);

	  /* look up a possible route with netbits netmask */
	  route = (struct multi_route *) hash_lookup (m->vhash, &tryaddr);

	  if (route && multi_route_defined (m, route))
	    {
	      /* found an applicable route, cache host route */
	      struct multi_instance *mi = route->instance;
	      multi_learn_addr (m, mi, addr, MULTI_ROUTE_CACHE|MULTI_ROUTE_AGEABLE);
	      ret = mi;
	      break;
	    }
	}
      
      mroute_helper_unlock (rh);
    }
  
#ifdef ENABLE_DEBUG
  if (check_debug_level (D_MULTI_DEBUG))
    {
      struct gc_arena gc = gc_new ();
      const char *addr_text = mroute_addr_print (addr, &gc);
      if (ret)
	{
	  dmsg (D_MULTI_DEBUG, "GET INST BY VIRT: %s -> %s via %s",
	       addr_text,
	       multi_instance_string (ret, false, &gc),
	       mroute_addr_print (&route->addr, &gc));
	}
      else
	{
	  dmsg (D_MULTI_DEBUG, "GET INST BY VIRT: %s [failed]",
	       addr_text);
	}
      gc_free (&gc);
    }
#endif

  ASSERT (!(ret && ret->halt));
  return ret;
}

/*
 * Helper function to multi_learn_addr().
 */
static struct multi_instance *
multi_learn_in_addr_t (struct multi_context *m,
		       struct multi_instance *mi,
		       in_addr_t a,
		       int netbits, /* -1 if host route, otherwise # of network bits in address */
		       bool primary)
{
  struct openvpn_sockaddr remote_si;
  struct mroute_addr addr;

  CLEAR (remote_si);
  remote_si.sa.sin_family = AF_INET;
  remote_si.sa.sin_addr.s_addr = htonl (a);
  ASSERT (mroute_extract_openvpn_sockaddr (&addr, &remote_si, false));

  if (netbits >= 0)
    {
      addr.type |= MR_WITH_NETBITS;
      addr.netbits = (uint8_t) netbits;
    }

  {
    struct multi_instance *owner = multi_learn_addr (m, mi, &addr, 0);
#ifdef MANAGEMENT_DEF_AUTH
    if (management && owner)
      management_learn_addr (management, &mi->context.c2.mda_context, &addr, primary);
#endif
    return owner;
  }
}

/*
 * A new client has connected, add routes (server -> client)
 * to internal routing table.
 */
static void
multi_add_iroutes (struct multi_context *m,
		   struct multi_instance *mi)
{
  struct gc_arena gc = gc_new ();
  const struct iroute *ir;
  if (TUNNEL_TYPE (mi->context.c1.tuntap) == DEV_TYPE_TUN)
    {
      mi->did_iroutes = true;
      for (ir = mi->context.options.iroutes; ir != NULL; ir = ir->next)
	{
	  if (ir->netbits >= 0)
	    msg (D_MULTI_LOW, "MULTI: internal route %s/%d -> %s",
		 print_in_addr_t (ir->network, 0, &gc),
		 ir->netbits,
		 multi_instance_string (mi, false, &gc));
	  else
	    msg (D_MULTI_LOW, "MULTI: internal route %s -> %s",
		 print_in_addr_t (ir->network, 0, &gc),
		 multi_instance_string (mi, false, &gc));

	  mroute_helper_add_iroute (m->route_helper, ir);
      
	  multi_learn_in_addr_t (m, mi, ir->network, ir->netbits, false);
	}
    }
  gc_free (&gc);
}

/*
 * Given an instance (new_mi), delete all other instances which use the
 * same common name.
 */
static void
multi_delete_dup (struct multi_context *m, struct multi_instance *new_mi)
{
  if (new_mi)
    {
      const char *new_cn = tls_common_name (new_mi->context.c2.tls_multi, true);
      if (new_cn)
	{
	  struct hash_iterator hi;
	  struct hash_element *he;
	  int count = 0;

	  hash_iterator_init (m->iter, &hi, true);
	  while ((he = hash_iterator_next (&hi)))
	    {
	      struct multi_instance *mi = (struct multi_instance *) he->value;
	      if (mi != new_mi && !mi->halt)
		{
		  const char *cn = tls_common_name (mi->context.c2.tls_multi, true);
		  if (cn && !strcmp (cn, new_cn))
		    {
		      mi->did_iter = false;
		      multi_close_instance (m, mi, false);
		      hash_iterator_delete_element (&hi);
		      ++count;
		    }
		}
	    }
	  hash_iterator_free (&hi);

	  if (count)
	    msg (D_MULTI_LOW, "MULTI: new connection by client '%s' will cause previous active sessions by this client to be dropped.  Remember to use the --duplicate-cn option if you want multiple clients using the same certificate or username to concurrently connect.", new_cn);
	}
    }
}

/*
 * Ensure that endpoint to be pushed to client
 * complies with --ifconfig-push-constraint directive.
 */
static bool
ifconfig_push_constraint_satisfied (const struct context *c)
{
  const struct options *o = &c->options;
  if (o->push_ifconfig_constraint_defined && c->c2.push_ifconfig_defined)
    return (o->push_ifconfig_constraint_netmask & c->c2.push_ifconfig_local) == o->push_ifconfig_constraint_network;
  else
    return true;
}

/*
 * Select a virtual address for a new client instance.
 * Use an --ifconfig-push directive, if given (static IP).
 * Otherwise use an --ifconfig-pool address (dynamic IP). 
 */
static void
multi_select_virtual_addr (struct multi_context *m, struct multi_instance *mi)
{
  struct gc_arena gc = gc_new ();

  /*
   * If ifconfig addresses were set by dynamic config file,
   * release pool addresses, otherwise keep them.
   */
  if (mi->context.options.push_ifconfig_defined)
    {
      /* ifconfig addresses were set statically,
	 release dynamic allocation */
      if (mi->vaddr_handle >= 0)
	{
	  ifconfig_pool_release (m->ifconfig_pool, mi->vaddr_handle, true);
	  mi->vaddr_handle = -1;
	}

      mi->context.c2.push_ifconfig_defined = true;
      mi->context.c2.push_ifconfig_local = mi->context.options.push_ifconfig_local;
      mi->context.c2.push_ifconfig_remote_netmask = mi->context.options.push_ifconfig_remote_netmask;
    }
  else if (m->ifconfig_pool && mi->vaddr_handle < 0) /* otherwise, choose a pool address */
    {
      in_addr_t local=0, remote=0;
      const char *cn = NULL;

      if (!mi->context.options.duplicate_cn)
	cn = tls_common_name (mi->context.c2.tls_multi, true);

      mi->vaddr_handle = ifconfig_pool_acquire (m->ifconfig_pool, &local, &remote, cn);
      if (mi->vaddr_handle >= 0)
	{
	  const int tunnel_type = TUNNEL_TYPE (mi->context.c1.tuntap);
	  const int tunnel_topology = TUNNEL_TOPOLOGY (mi->context.c1.tuntap);

	  /* set push_ifconfig_remote_netmask from pool ifconfig address(es) */
	  mi->context.c2.push_ifconfig_local = remote;
	  if (tunnel_type == DEV_TYPE_TAP || (tunnel_type == DEV_TYPE_TUN && tunnel_topology == TOP_SUBNET))
	    {
	      mi->context.c2.push_ifconfig_remote_netmask = mi->context.options.ifconfig_pool_netmask;
	      if (!mi->context.c2.push_ifconfig_remote_netmask)
		mi->context.c2.push_ifconfig_remote_netmask = mi->context.c1.tuntap->remote_netmask;
	    }
	  else if (tunnel_type == DEV_TYPE_TUN)
	    {
	      if (tunnel_topology == TOP_P2P)		    
		mi->context.c2.push_ifconfig_remote_netmask = mi->context.c1.tuntap->local;
	      else if (tunnel_topology == TOP_NET30)		    
		mi->context.c2.push_ifconfig_remote_netmask = local;
	    }

	  if (mi->context.c2.push_ifconfig_remote_netmask)
	    mi->context.c2.push_ifconfig_defined = true;
	  else
	    msg (D_MULTI_ERRORS, "MULTI: no --ifconfig-pool netmask parameter is available to push to %s",
		 multi_instance_string (mi, false, &gc));
	}
      else
	{
	  msg (D_MULTI_ERRORS, "MULTI: no free --ifconfig-pool addresses are available");
	}
    }
  gc_free (&gc);
}

/*
 * Set virtual address environmental variables.
 */
static void
multi_set_virtual_addr_env (struct multi_context *m, struct multi_instance *mi)
{
  setenv_del (mi->context.c2.es, "ifconfig_pool_local_ip");
  setenv_del (mi->context.c2.es, "ifconfig_pool_remote_ip");
  setenv_del (mi->context.c2.es, "ifconfig_pool_netmask");

  if (mi->context.c2.push_ifconfig_defined)
    {
      const int tunnel_type = TUNNEL_TYPE (mi->context.c1.tuntap);
      const int tunnel_topology = TUNNEL_TOPOLOGY (mi->context.c1.tuntap);

      setenv_in_addr_t (mi->context.c2.es,
			"ifconfig_pool_remote_ip",
			mi->context.c2.push_ifconfig_local,
			SA_SET_IF_NONZERO);

      if (tunnel_type == DEV_TYPE_TAP || (tunnel_type == DEV_TYPE_TUN && tunnel_topology == TOP_SUBNET))
	{
	  setenv_in_addr_t (mi->context.c2.es,
			    "ifconfig_pool_netmask",
			    mi->context.c2.push_ifconfig_remote_netmask,
			    SA_SET_IF_NONZERO);
	}
      else if (tunnel_type == DEV_TYPE_TUN)
	{
	  setenv_in_addr_t (mi->context.c2.es,
			    "ifconfig_pool_local_ip",
			    mi->context.c2.push_ifconfig_remote_netmask,
			    SA_SET_IF_NONZERO);
	}
    }
}

/*
 * Called after client-connect script is called
 */
static void
multi_client_connect_post (struct multi_context *m,
			   struct multi_instance *mi,
			   const char *dc_file,
			   unsigned int option_permissions_mask,
			   unsigned int *option_types_found)
{
  /* Did script generate a dynamic config file? */
  if (test_file (dc_file))
    {
      options_server_import (&mi->context.options,
			     dc_file,
			     D_IMPORT_ERRORS|M_OPTERR,
			     option_permissions_mask,
			     option_types_found,
			     mi->context.c2.es);

      if (!delete_file (dc_file))
	msg (D_MULTI_ERRORS, "MULTI: problem deleting temporary file: %s",
	     dc_file);

      /*
       * If the --client-connect script generates a config file
       * with an --ifconfig-push directive, it will override any
       * --ifconfig-push directive from the --client-config-dir
       * directory or any --ifconfig-pool dynamic address.
       */
      multi_select_virtual_addr (m, mi);
      multi_set_virtual_addr_env (m, mi);
    }
}

#ifdef ENABLE_PLUGIN

/*
 * Called after client-connect plug-in is called
 */
static void
multi_client_connect_post_plugin (struct multi_context *m,
				  struct multi_instance *mi,
				  const struct plugin_return *pr,
				  unsigned int option_permissions_mask,
				  unsigned int *option_types_found)
{
  struct plugin_return config;

  plugin_return_get_column (pr, &config, "config");

  /* Did script generate a dynamic config file? */
  if (plugin_return_defined (&config))
    {
      int i;
      for (i = 0; i < config.n; ++i)
	{
	  if (config.list[i] && config.list[i]->value)
	    options_string_import (&mi->context.options,
				   config.list[i]->value,
				   D_IMPORT_ERRORS|M_OPTERR,
				   option_permissions_mask,
				   option_types_found,
				   mi->context.c2.es);
	}

      /*
       * If the --client-connect script generates a config file
       * with an --ifconfig-push directive, it will override any
       * --ifconfig-push directive from the --client-config-dir
       * directory or any --ifconfig-pool dynamic address.
       */
      multi_select_virtual_addr (m, mi);
      multi_set_virtual_addr_env (m, mi);
    }
}

#endif

#ifdef MANAGEMENT_DEF_AUTH

/*
 * Called to load management-derived client-connect config
 */
static void
multi_client_connect_mda (struct multi_context *m,
			  struct multi_instance *mi,
			  const struct buffer_list *config,
			  unsigned int option_permissions_mask,
			  unsigned int *option_types_found)
{
  if (config)
    {
      struct buffer_entry *be;
  
      for (be = config->head; be != NULL; be = be->next)
	{
	  const char *opt = BSTR(&be->buf);
	  options_string_import (&mi->context.options,
				 opt,
				 D_IMPORT_ERRORS|M_OPTERR,
				 option_permissions_mask,
				 option_types_found,
				 mi->context.c2.es);
	}

      /*
       * If the --client-connect script generates a config file
       * with an --ifconfig-push directive, it will override any
       * --ifconfig-push directive from the --client-config-dir
       * directory or any --ifconfig-pool dynamic address.
       */
      multi_select_virtual_addr (m, mi);
      multi_set_virtual_addr_env (m, mi);
    }
}

#endif

static void
multi_client_connect_setenv (struct multi_context *m,
			     struct multi_instance *mi)
{
  struct gc_arena gc = gc_new ();

  /* setenv incoming cert common name for script */
  setenv_str (mi->context.c2.es, "common_name", tls_common_name (mi->context.c2.tls_multi, true));

  /* setenv client real IP address */
  setenv_trusted (mi->context.c2.es, get_link_socket_info (&mi->context));

  /* setenv client virtual IP address */
  multi_set_virtual_addr_env (m, mi);

  /* setenv connection time */
  {
    const char *created_ascii = time_string (mi->created, 0, false, &gc);
    setenv_str (mi->context.c2.es, "time_ascii", created_ascii);
    setenv_unsigned (mi->context.c2.es, "time_unix", (unsigned int)mi->created);
  }

  gc_free (&gc);
}

/*
 * Called as soon as the SSL/TLS connection authenticates.
 *
 * Instance-specific directives to be processed:
 *
 *   iroute start-ip end-ip
 *   ifconfig-push local remote-netmask
 *   push
 */
static void
multi_connection_established (struct multi_context *m, struct multi_instance *mi)
{
  if (tls_authentication_status (mi->context.c2.tls_multi, 0) == TLS_AUTHENTICATION_SUCCEEDED)
    {
      struct gc_arena gc = gc_new ();
      unsigned int option_types_found = 0;

      const unsigned int option_permissions_mask =
	  OPT_P_INSTANCE
	| OPT_P_INHERIT
	| OPT_P_PUSH
	| OPT_P_TIMER
	| OPT_P_CONFIG
	| OPT_P_ECHO
	| OPT_P_COMP
	| OPT_P_SOCKFLAGS;

      int cc_succeeded = true; /* client connect script status */
      int cc_succeeded_count = 0;

      ASSERT (mi->context.c1.tuntap);

      /* lock down the common name so it can't change during future TLS renegotiations */
      tls_lock_common_name (mi->context.c2.tls_multi);

      /* generate a msg() prefix for this client instance */
      generate_prefix (mi);

      /* delete instances of previous clients with same common-name */
      if (!mi->context.options.duplicate_cn)
	multi_delete_dup (m, mi);

      /* reset pool handle to null */
      mi->vaddr_handle = -1;

      /*
       * Try to source a dynamic config file from the
       * --client-config-dir directory.
       */
      if (mi->context.options.client_config_dir)
	{
	  const char *ccd_file;
	  
	  ccd_file = gen_path (mi->context.options.client_config_dir,
			       tls_common_name (mi->context.c2.tls_multi, false),
			       &gc);

	  /* try common-name file */
	  if (test_file (ccd_file))
	    {
	      options_server_import (&mi->context.options,
				     ccd_file,
				     D_IMPORT_ERRORS|M_OPTERR,
				     option_permissions_mask,
				     &option_types_found,
				     mi->context.c2.es);
	    }
	  else /* try default file */
	    {
	      ccd_file = gen_path (mi->context.options.client_config_dir,
				   CCD_DEFAULT,
				   &gc);

	      if (test_file (ccd_file))
		{
		  options_server_import (&mi->context.options,
					 ccd_file,
					 D_IMPORT_ERRORS|M_OPTERR,
					 option_permissions_mask,
					 &option_types_found,
					 mi->context.c2.es);
		}
	    }
	}

      /*
       * Select a virtual address from either --ifconfig-push in --client-config-dir file
       * or --ifconfig-pool.
       */
      multi_select_virtual_addr (m, mi);

      /* do --client-connect setenvs */
      multi_client_connect_setenv (m, mi);

#ifdef ENABLE_PLUGIN
      /*
       * Call client-connect plug-in.
       */

      /* deprecated callback, use a file for passing back return info */
      if (plugin_defined (mi->context.plugins, OPENVPN_PLUGIN_CLIENT_CONNECT))
	{
	  struct argv argv = argv_new ();
	  const char *dc_file = create_temp_filename (mi->context.options.tmp_dir, "cc", &gc);
	  argv_printf (&argv, "%s", dc_file);
	  delete_file (dc_file);
	  if (plugin_call (mi->context.plugins, OPENVPN_PLUGIN_CLIENT_CONNECT, &argv, NULL, mi->context.c2.es) != OPENVPN_PLUGIN_FUNC_SUCCESS)
	    {
	      msg (M_WARN, "WARNING: client-connect plugin call failed");
	      cc_succeeded = false;
	    }
	  else
	    {
	      multi_client_connect_post (m, mi, dc_file, option_permissions_mask, &option_types_found);
	      ++cc_succeeded_count;
	    }
	  argv_reset (&argv);
	}

      /* V2 callback, use a plugin_return struct for passing back return info */
      if (plugin_defined (mi->context.plugins, OPENVPN_PLUGIN_CLIENT_CONNECT_V2))
	{
	  struct plugin_return pr;

	  plugin_return_init (&pr);

	  if (plugin_call (mi->context.plugins, OPENVPN_PLUGIN_CLIENT_CONNECT_V2, NULL, &pr, mi->context.c2.es) != OPENVPN_PLUGIN_FUNC_SUCCESS)
	    {
	      msg (M_WARN, "WARNING: client-connect-v2 plugin call failed");
	      cc_succeeded = false;
	    }
	  else
	    {
	      multi_client_connect_post_plugin (m, mi, &pr, option_permissions_mask, &option_types_found);
	      ++cc_succeeded_count;
	    }

	  plugin_return_free (&pr);
	}
#endif

      /*
       * Run --client-connect script.
       */
      if (mi->context.options.client_connect_script && cc_succeeded)
	{
	  struct argv argv = argv_new ();
	  const char *dc_file = NULL;

	  setenv_str (mi->context.c2.es, "script_type", "client-connect");

	  dc_file = create_temp_filename (mi->context.options.tmp_dir, "cc", &gc);

	  delete_file (dc_file);

	  argv_printf (&argv, "%s %s",
		       mi->context.options.client_connect_script,
		       dc_file);

	  if (openvpn_execve_check (&argv, mi->context.c2.es, S_SCRIPT, "client-connect command failed"))
	    {
	      multi_client_connect_post (m, mi, dc_file, option_permissions_mask, &option_types_found);
	      ++cc_succeeded_count;
	    }
	  else
	    cc_succeeded = false;

	  argv_reset (&argv);
	}

      /*
       * Check for client-connect script left by management interface client
       */
#ifdef MANAGEMENT_DEF_AUTH
      if (cc_succeeded && mi->cc_config)
	{
	  multi_client_connect_mda (m, mi, mi->cc_config, option_permissions_mask, &option_types_found);
	  ++cc_succeeded_count;
	}
#endif

      /*
       * Check for "disable" directive in client-config-dir file
       * or config file generated by --client-connect script.
       */
      if (mi->context.options.disable)
	{
	  msg (D_MULTI_ERRORS, "MULTI: client has been rejected due to 'disable' directive");
	  cc_succeeded = false;
	}

      if (cc_succeeded)
	{
	  /*
	   * Process sourced options.
	   */
	  do_deferred_options (&mi->context, option_types_found);

	  /*
	   * make sure we got ifconfig settings from somewhere
	   */
	  if (!mi->context.c2.push_ifconfig_defined)
	    {
	      msg (D_MULTI_ERRORS, "MULTI: no dynamic or static remote --ifconfig address is available for %s",
		   multi_instance_string (mi, false, &gc));
	    }

	  /*
	   * make sure that ifconfig settings comply with constraints
	   */
	  if (!ifconfig_push_constraint_satisfied (&mi->context))
	    {
	      /* JYFIXME -- this should cause the connection to fail */
	      msg (D_MULTI_ERRORS, "MULTI ERROR: primary virtual IP for %s (%s) violates tunnel network/netmask constraint (%s/%s)",
		   multi_instance_string (mi, false, &gc),
		   print_in_addr_t (mi->context.c2.push_ifconfig_local, 0, &gc),
		   print_in_addr_t (mi->context.options.push_ifconfig_constraint_network, 0, &gc),
		   print_in_addr_t (mi->context.options.push_ifconfig_constraint_netmask, 0, &gc));
	    }

	  /*
	   * For routed tunnels, set up internal route to endpoint
	   * plus add all iroute routes.
	   */
	  if (TUNNEL_TYPE (mi->context.c1.tuntap) == DEV_TYPE_TUN)
	    {
	      if (mi->context.c2.push_ifconfig_defined)
		{
		  multi_learn_in_addr_t (m, mi, mi->context.c2.push_ifconfig_local, -1, true);
		  msg (D_MULTI_LOW, "MULTI: primary virtual IP for %s: %s",
		       multi_instance_string (mi, false, &gc),
		       print_in_addr_t (mi->context.c2.push_ifconfig_local, 0, &gc));
		}

	      /* add routes locally, pointing to new client, if
		 --iroute options have been specified */
	      multi_add_iroutes (m, mi);

	      /*
	       * iroutes represent subnets which are "owned" by a particular
	       * client.  Therefore, do not actually push a route to a client
	       * if it matches one of the client's iroutes.
	       */
	      remove_iroutes_from_push_route_list (&mi->context.options);
	    }
	  else if (mi->context.options.iroutes)
	    {
	      msg (D_MULTI_ERRORS, "MULTI: --iroute options rejected for %s -- iroute only works with tun-style tunnels",
		   multi_instance_string (mi, false, &gc));
	    }

	  /* set our client's VPN endpoint for status reporting purposes */
	  mi->reporting_addr = mi->context.c2.push_ifconfig_local;

	  /* set context-level authentication flag */
	  mi->context.c2.context_auth = CAS_SUCCEEDED;
	}
      else
	{
	  /* set context-level authentication flag */
	  mi->context.c2.context_auth = cc_succeeded_count ? CAS_PARTIAL : CAS_FAILED;
	}

      /* set flag so we don't get called again */
      mi->connection_established_flag = true;

#ifdef MANAGEMENT_DEF_AUTH
      if (management)
	management_connection_established (management, &mi->context.c2.mda_context);
#endif

      gc_free (&gc);
    }

  /*
   * Reply now to client's PUSH_REQUEST query
   */
  mi->context.c2.push_reply_deferred = false;
}

/*
 * Add a mbuf buffer to a particular
 * instance.
 */
void
multi_add_mbuf (struct multi_context *m,
		struct multi_instance *mi,
		struct mbuf_buffer *mb)
{
  if (multi_output_queue_ready (m, mi))
    {
      struct mbuf_item item;
      item.buffer = mb;
      item.instance = mi;
      mbuf_add_item (m->mbuf, &item);
    }
  else
    {
      msg (D_MULTI_DROPPED, "MULTI: packet dropped due to output saturation (multi_add_mbuf)");
    }
}

/*
 * Add a packet to a client instance output queue.
 */
static inline void
multi_unicast (struct multi_context *m,
	       const struct buffer *buf,
	       struct multi_instance *mi)
{
  struct mbuf_buffer *mb;

  if (BLEN (buf) > 0)
    {
      mb = mbuf_alloc_buf (buf);
      mb->flags = MF_UNICAST;
      multi_add_mbuf (m, mi, mb);
      mbuf_free_buf (mb);
    }
}

/*
 * Broadcast a packet to all clients.
 */
static void
multi_bcast (struct multi_context *m,
	     const struct buffer *buf,
	     const struct multi_instance *sender_instance,
	     const struct mroute_addr *sender_addr)
{
  struct hash_iterator hi;
  struct hash_element *he;
  struct multi_instance *mi;
  struct mbuf_buffer *mb;

  if (BLEN (buf) > 0)
    {
      perf_push (PERF_MULTI_BCAST);
#ifdef MULTI_DEBUG_EVENT_LOOP
      printf ("BCAST len=%d\n", BLEN (buf));
#endif
      mb = mbuf_alloc_buf (buf);
      hash_iterator_init (m->iter, &hi, true);

      while ((he = hash_iterator_next (&hi)))
	{
	  mi = (struct multi_instance *) he->value;
	  if (mi != sender_instance && !mi->halt)
	    {
#ifdef ENABLE_PF
	      if (sender_instance)
		{
		  if (!pf_c2c_test (&sender_instance->context, &mi->context, "bcast_c2c"))
		    {
		      msg (D_PF_DROPPED_BCAST, "PF: client[%s] -> client[%s] packet dropped by BCAST packet filter",
			   mi_prefix (sender_instance),
			   mi_prefix (mi));
		      continue;
		    }
		}
	      if (sender_addr)
		{
		  if (!pf_addr_test (&mi->context, sender_addr, "bcast_src_addr"))
		    {
		      struct gc_arena gc = gc_new ();
		      msg (D_PF_DROPPED_BCAST, "PF: addr[%s] -> client[%s] packet dropped by BCAST packet filter",
			   mroute_addr_print_ex (sender_addr, MAPF_SHOW_ARP, &gc),
			   mi_prefix (mi));
		      gc_free (&gc);
		      continue;
		    }
		}
#endif
	      multi_add_mbuf (m, mi, mb);
	    }
	}

      hash_iterator_free (&hi);
      mbuf_free_buf (mb);
      perf_pop ();
    }
}

/*
 * Given a time delta, indicating that we wish to be
 * awoken by the scheduler at time now + delta, figure
 * a sigma parameter (in microseconds) that represents
 * a sort of fuzz factor around delta, so that we're
 * really telling the scheduler to wake us up any time
 * between now + delta - sigma and now + delta + sigma.
 *
 * The sigma parameter helps the scheduler to run more efficiently.
 * Sigma should be no larger than TV_WITHIN_SIGMA_MAX_USEC
 */
static inline unsigned int
compute_wakeup_sigma (const struct timeval *delta)
{
  if (delta->tv_sec < 1)
    {
      /* if < 1 sec, fuzz = # of microseconds / 8 */
      return delta->tv_usec >> 3;
    }
  else
    {
      /* if < 10 minutes, fuzz = 13.1% of timeout */
      if (delta->tv_sec < 600)
	return delta->tv_sec << 17;
      else
	return 120000000; /* if >= 10 minutes, fuzz = 2 minutes */
    }
}

/*
 * Figure instance-specific timers, convert
 * earliest to absolute time in mi->wakeup,
 * call scheduler with our future wakeup time.
 *
 * Also close context on signal.
 */
bool
multi_process_post (struct multi_context *m, struct multi_instance *mi, const unsigned int flags)
{
  bool ret = true;

  if (!IS_SIG (&mi->context) && ((flags & MPP_PRE_SELECT) || ((flags & MPP_CONDITIONAL_PRE_SELECT) && !ANY_OUT (&mi->context))))
    {
      /* figure timeouts and fetch possible outgoing
	 to_link packets (such as ping or TLS control) */
      pre_select (&mi->context);

      if (!IS_SIG (&mi->context))
	{
	  /* calculate an absolute wakeup time */
	  ASSERT (!openvpn_gettimeofday (&mi->wakeup, NULL));
	  tv_add (&mi->wakeup, &mi->context.c2.timeval);

	  /* tell scheduler to wake us up at some point in the future */
	  schedule_add_entry (m->schedule,
			      (struct schedule_entry *) mi,
			      &mi->wakeup,
			      compute_wakeup_sigma (&mi->context.c2.timeval));

	  /* connection is "established" when SSL/TLS key negotiation succeeds
	     and (if specified) auth user/pass succeeds */
	  if (!mi->connection_established_flag && CONNECTION_ESTABLISHED (&mi->context))
	    multi_connection_established (m, mi);
	}
    }

  if (IS_SIG (&mi->context))
    {
      if (flags & MPP_CLOSE_ON_SIGNAL)
	{
	  multi_close_instance_on_signal (m, mi);
	  ret = false;
	}
    }
  else
    {
      /* continue to pend on output? */
      multi_set_pending (m, ANY_OUT (&mi->context) ? mi : NULL);

#ifdef MULTI_DEBUG_EVENT_LOOP
      printf ("POST %s[%d] to=%d lo=%d/%d w=%d/%d\n",
	      id(mi),
	      (int) (mi == m->pending),
	      mi ? mi->context.c2.to_tun.len : -1,
	      mi ? mi->context.c2.to_link.len : -1,
	      (mi && mi->context.c2.fragment) ? mi->context.c2.fragment->outgoing.len : -1,
	      (int)mi->context.c2.timeval.tv_sec,
	      (int)mi->context.c2.timeval.tv_usec);
#endif
    }

  if ((flags & MPP_RECORD_TOUCH) && m->mpp_touched)
    *m->mpp_touched = mi;

  return ret;
}

/*
 * Process packets in the TCP/UDP socket -> TUN/TAP interface direction,
 * i.e. client -> server direction.
 */
bool
multi_process_incoming_link (struct multi_context *m, struct multi_instance *instance, const unsigned int mpp_flags)
{
  struct gc_arena gc = gc_new ();

  struct context *c;
  struct mroute_addr src, dest;
  unsigned int mroute_flags;
  struct multi_instance *mi;
  bool ret = true;

  if (m->pending)
    return true;

  if (!instance)
    {
#ifdef MULTI_DEBUG_EVENT_LOOP
      printf ("TCP/UDP -> TUN [%d]\n", BLEN (&m->top.c2.buf));
#endif
      multi_set_pending (m, multi_get_create_instance_udp (m));
    }
  else
    multi_set_pending (m, instance);

  if (m->pending)
    {
      set_prefix (m->pending);

      /* get instance context */
      c = &m->pending->context;

      if (!instance)
	{
	  /* transfer packet pointer from top-level context buffer to instance */
	  c->c2.buf = m->top.c2.buf;

	  /* transfer from-addr from top-level context buffer to instance */
	  c->c2.from = m->top.c2.from;
	}

      if (BLEN (&c->c2.buf) > 0)
	{
	  /* decrypt in instance context */
	  process_incoming_link (c);

	  if (TUNNEL_TYPE (m->top.c1.tuntap) == DEV_TYPE_TUN)
	    {
	      /* extract packet source and dest addresses */
	      mroute_flags = mroute_extract_addr_from_packet (&src,
							      &dest,
							      NULL,
							      NULL,
							      &c->c2.to_tun,
							      DEV_TYPE_TUN);

	      /* drop packet if extract failed */
	      if (!(mroute_flags & MROUTE_EXTRACT_SUCCEEDED))
		{
		  c->c2.to_tun.len = 0;
		}
	      /* make sure that source address is associated with this client */
	      else if (multi_get_instance_by_virtual_addr (m, &src, true) != m->pending)
		{
		  msg (D_MULTI_DROPPED, "MULTI: bad source address from client [%s], packet dropped",
		       mroute_addr_print (&src, &gc));
		  c->c2.to_tun.len = 0;
		}
	      /* client-to-client communication enabled? */
	      else if (m->enable_c2c)
		{
		  /* multicast? */
		  if (mroute_flags & MROUTE_EXTRACT_MCAST)
		    {
		      /* for now, treat multicast as broadcast */
		      multi_bcast (m, &c->c2.to_tun, m->pending, NULL);
		    }
		  else /* possible client to client routing */
		    {
		      ASSERT (!(mroute_flags & MROUTE_EXTRACT_BCAST));
		      mi = multi_get_instance_by_virtual_addr (m, &dest, true);
		  
		      /* if dest addr is a known client, route to it */
		      if (mi)
			{
#ifdef ENABLE_PF
			  if (!pf_c2c_test (c, &mi->context, "tun_c2c"))
			    {
			      msg (D_PF_DROPPED, "PF: client -> client[%s] packet dropped by TUN packet filter",
				   mi_prefix (mi));
			    }
			  else
#endif
			    {
			      multi_unicast (m, &c->c2.to_tun, mi);
			      register_activity (c, BLEN(&c->c2.to_tun));
			    }
			  c->c2.to_tun.len = 0;
			}
		    }
		}
#ifdef ENABLE_PF
	      if (c->c2.to_tun.len && !pf_addr_test (c, &dest, "tun_dest_addr"))
		{
		  msg (D_PF_DROPPED, "PF: client -> addr[%s] packet dropped by TUN packet filter",
		       mroute_addr_print_ex (&dest, MAPF_SHOW_ARP, &gc));
		  c->c2.to_tun.len = 0;
		}
#endif
	    }
	  else if (TUNNEL_TYPE (m->top.c1.tuntap) == DEV_TYPE_TAP)
	    {
#ifdef ENABLE_PF
	      struct mroute_addr edest;
	      mroute_addr_reset (&edest);
#endif
	      /* extract packet source and dest addresses */
	      mroute_flags = mroute_extract_addr_from_packet (&src,
							      &dest,
							      NULL,
#ifdef ENABLE_PF
							      &edest,
#else
							      NULL,
#endif
							      &c->c2.to_tun,
							      DEV_TYPE_TAP);

	      if (mroute_flags & MROUTE_EXTRACT_SUCCEEDED)
		{
		  if (multi_learn_addr (m, m->pending, &src, 0) == m->pending)
		    {
		      /* check for broadcast */
		      if (m->enable_c2c)
			{
			  if (mroute_flags & (MROUTE_EXTRACT_BCAST|MROUTE_EXTRACT_MCAST))
			    {
			      multi_bcast (m, &c->c2.to_tun, m->pending, NULL);
			    }
			  else /* try client-to-client routing */
			    {
			      mi = multi_get_instance_by_virtual_addr (m, &dest, false);

			      /* if dest addr is a known client, route to it */
			      if (mi)
				{
#ifdef ENABLE_PF
				  if (!pf_c2c_test (c, &mi->context, "tap_c2c"))
				    {
				      msg (D_PF_DROPPED, "PF: client -> client[%s] packet dropped by TAP packet filter",
					   mi_prefix (mi));
				    }
				  else
#endif
				    {
				      multi_unicast (m, &c->c2.to_tun, mi);
				      register_activity (c, BLEN(&c->c2.to_tun));
				    }
				  c->c2.to_tun.len = 0;
				}
			    }
			}
#ifdef ENABLE_PF
		      if (c->c2.to_tun.len && !pf_addr_test (c, &edest, "tap_dest_addr"))
			{
			  msg (D_PF_DROPPED, "PF: client -> addr[%s] packet dropped by TAP packet filter",
			       mroute_addr_print_ex (&edest, MAPF_SHOW_ARP, &gc));
			  c->c2.to_tun.len = 0;
			}
#endif
		    }
		  else
		    {
		      msg (D_MULTI_DROPPED, "MULTI: bad source address from client [%s], packet dropped",
			   mroute_addr_print (&src, &gc));
		      c->c2.to_tun.len = 0;
		    }
		}
	      else
		{
		  c->c2.to_tun.len = 0;
		}
	    }
	}

      /* postprocess and set wakeup */
      ret = multi_process_post (m, m->pending, mpp_flags);

      clear_prefix ();
    }

  gc_free (&gc);
  return ret;
}

/*
 * Process packets in the TUN/TAP interface -> TCP/UDP socket direction,
 * i.e. server -> client direction.
 */
bool
multi_process_incoming_tun (struct multi_context *m, const unsigned int mpp_flags)
{
  struct gc_arena gc = gc_new ();
  bool ret = true;

  if (BLEN (&m->top.c2.buf) > 0)
    {
      unsigned int mroute_flags;
      struct mroute_addr src, dest;
      const int dev_type = TUNNEL_TYPE (m->top.c1.tuntap);

#ifdef ENABLE_PF
      struct mroute_addr esrc, *e1, *e2;
      if (dev_type == DEV_TYPE_TUN)
	{
	  e1 = NULL;
	  e2 = &src;
	}
      else
	{
	  e1 = e2 = &esrc;
	  mroute_addr_reset (&esrc);
	}
#endif

#ifdef MULTI_DEBUG_EVENT_LOOP
      printf ("TUN -> TCP/UDP [%d]\n", BLEN (&m->top.c2.buf));
#endif

      if (m->pending)
	return true;

      /* 
       * Route an incoming tun/tap packet to
       * the appropriate multi_instance object.
       */

      mroute_flags = mroute_extract_addr_from_packet (&src,
						      &dest,
#ifdef ENABLE_PF
						      e1,
#else
						      NULL,
#endif
						      NULL,
						      &m->top.c2.buf,
						      dev_type);

      if (mroute_flags & MROUTE_EXTRACT_SUCCEEDED)
	{
	  struct context *c;

	  /* broadcast or multicast dest addr? */
	  if (mroute_flags & (MROUTE_EXTRACT_BCAST|MROUTE_EXTRACT_MCAST))
	    {
	      /* for now, treat multicast as broadcast */
#ifdef ENABLE_PF
	      multi_bcast (m, &m->top.c2.buf, NULL, e2);
#else
	      multi_bcast (m, &m->top.c2.buf, NULL, NULL);
#endif
	    }
	  else
	    {
	      multi_set_pending (m, multi_get_instance_by_virtual_addr (m, &dest, dev_type == DEV_TYPE_TUN));

	      if (m->pending)
		{
		  /* get instance context */
		  c = &m->pending->context;
		  
		  set_prefix (m->pending);

#ifdef ENABLE_PF
		  if (!pf_addr_test (c, e2, "tun_tap_src_addr"))
		    {
		      msg (D_PF_DROPPED, "PF: addr[%s] -> client packet dropped by packet filter",
			   mroute_addr_print_ex (&src, MAPF_SHOW_ARP, &gc));
		      buf_reset_len (&c->c2.buf);
		    }
		  else
#endif
		  {
		    if (multi_output_queue_ready (m, m->pending))
		      {
			/* transfer packet pointer from top-level context buffer to instance */
			c->c2.buf = m->top.c2.buf;
		      }
		    else
		      {
			/* drop packet */
			msg (D_MULTI_DROPPED, "MULTI: packet dropped due to output saturation (multi_process_incoming_tun)");
			buf_reset_len (&c->c2.buf);
		      }
		  }
	      
		  /* encrypt in instance context */
		  process_incoming_tun (c);

		  /* postprocess and set wakeup */
		  ret = multi_process_post (m, m->pending, mpp_flags);

		  clear_prefix ();
		}
	    }
	}
    }
  gc_free (&gc);
  return ret;
}

/*
 * Process a possible client-to-client/bcast/mcast message in the
 * queue.
 */
struct multi_instance *
multi_get_queue (struct mbuf_set *ms)
{
  struct mbuf_item item;

  if (mbuf_extract_item (ms, &item, true)) /* cleartext IP packet */
    {
      unsigned int pipv4_flags = PIPV4_PASSTOS;

      set_prefix (item.instance);
      item.instance->context.c2.buf = item.buffer->buf;
      if (item.buffer->flags & MF_UNICAST) /* --mssfix doesn't make sense for broadcast or multicast */
	pipv4_flags |= PIPV4_MSSFIX;
      process_ipv4_header (&item.instance->context, pipv4_flags, &item.instance->context.c2.buf);
      encrypt_sign (&item.instance->context, true);
      mbuf_free_buf (item.buffer);

      dmsg (D_MULTI_DEBUG, "MULTI: C2C/MCAST/BCAST");

      clear_prefix ();
      return item.instance;
    }
  else
    {
      return NULL;
    }
}

/*
 * Called when an I/O wait times out.  Usually means that a particular
 * client instance object needs timer-based service.
 */
bool
multi_process_timeout (struct multi_context *m, const unsigned int mpp_flags)
{
  bool ret = true;

#ifdef MULTI_DEBUG_EVENT_LOOP
  printf ("%s -> TIMEOUT\n", id(m->earliest_wakeup));
#endif

  /* instance marked for wakeup? */
  if (m->earliest_wakeup)
    {
      set_prefix (m->earliest_wakeup);
      ret = multi_process_post (m, m->earliest_wakeup, mpp_flags);
      m->earliest_wakeup = NULL;
      clear_prefix ();
    }
  return ret;
}

/*
 * Drop a TUN/TAP outgoing packet..
 */
void
multi_process_drop_outgoing_tun (struct multi_context *m, const unsigned int mpp_flags)
{
  struct multi_instance *mi = m->pending;

  ASSERT (mi);

  set_prefix (mi);

  msg (D_MULTI_ERRORS, "MULTI: Outgoing TUN queue full, dropped packet len=%d",
       mi->context.c2.to_tun.len);

  buf_reset (&mi->context.c2.to_tun);

  multi_process_post (m, mi, mpp_flags);
  clear_prefix ();
}

/*
 * Per-client route quota management
 */

void
route_quota_exceeded (const struct multi_context *m, const struct multi_instance *mi)
{
  struct gc_arena gc = gc_new ();
  msg (D_ROUTE_QUOTA, "MULTI ROUTE: route quota (%d) exceeded for %s (see --max-routes-per-client option)",
	mi->context.options.max_routes_per_client,
	multi_instance_string (mi, false, &gc));
  gc_free (&gc);
}

#ifdef ENABLE_DEBUG
/*
 * Flood clients with random packets
 */
static void
gremlin_flood_clients (struct multi_context *m)
{
  const int level = GREMLIN_PACKET_FLOOD_LEVEL (m->top.options.gremlin);
  if (level)
    {
      struct gc_arena gc = gc_new ();
      struct buffer buf = alloc_buf_gc (BUF_SIZE (&m->top.c2.frame), &gc);
      struct packet_flood_parms parm = get_packet_flood_parms (level);
      int i;

      ASSERT (buf_init (&buf, FRAME_HEADROOM (&m->top.c2.frame)));
      parm.packet_size = min_int (parm.packet_size, MAX_RW_SIZE_TUN (&m->top.c2.frame));

      msg (D_GREMLIN, "GREMLIN_FLOOD_CLIENTS: flooding clients with %d packets of size %d",
	   parm.n_packets,
	   parm.packet_size);

      for (i = 0; i < parm.packet_size; ++i)
	ASSERT (buf_write_u8 (&buf, get_random () & 0xFF));

      for (i = 0; i < parm.n_packets; ++i)
	multi_bcast (m, &buf, NULL, NULL);

      gc_free (&gc);
    }
}
#endif

/*
 * Process timers in the top-level context
 */
void
multi_process_per_second_timers_dowork (struct multi_context *m)
{
  /* possibly reap instances/routes in vhash */
  multi_reap_process (m);

  /* possibly print to status log */
  if (m->top.c1.status_output)
    {
      if (status_trigger (m->top.c1.status_output))
	multi_print_status (m, m->top.c1.status_output, m->status_file_version);
    }

  /* possibly flush ifconfig-pool file */
  multi_ifconfig_pool_persist (m, false);

#ifdef ENABLE_DEBUG
  gremlin_flood_clients (m);
#endif
}

void
multi_top_init (struct multi_context *m, const struct context *top, const bool alloc_buffers)
{
  inherit_context_top (&m->top, top);
  m->top.c2.buffers = NULL;
  if (alloc_buffers)
    m->top.c2.buffers = init_context_buffers (&top->c2.frame);
}

void
multi_top_free (struct multi_context *m)
{
  close_context (&m->top, -1, CC_GC_FREE);
  free_context_buffers (m->top.c2.buffers);
}

/*
 * Return true if event loop should break,
 * false if it should continue.
 */
bool
multi_process_signal (struct multi_context *m)
{
  if (m->top.sig->signal_received == SIGUSR2)
    {
      struct status_output *so = status_open (NULL, 0, M_INFO, NULL, 0);
      multi_print_status (m, so, m->status_file_version);
      status_close (so);
      m->top.sig->signal_received = 0;
      return false;
    }
  return true;
}

/*
 * Called when an instance should be closed due to the
 * reception of a soft signal.
 */
void
multi_close_instance_on_signal (struct multi_context *m, struct multi_instance *mi)
{
  remap_signal (&mi->context);
  set_prefix (mi);
  print_signal (mi->context.sig, "client-instance", D_MULTI_LOW);
  clear_prefix ();
  multi_close_instance (m, mi, false);
}

static void
multi_signal_instance (struct multi_context *m, struct multi_instance *mi, const int sig)
{
  mi->context.sig->signal_received = sig;
  multi_close_instance_on_signal (m, mi);
}

/*
 * Management subsystem callbacks
 */

#ifdef ENABLE_MANAGEMENT

static void
management_callback_status (void *arg, const int version, struct status_output *so)
{
  struct multi_context *m = (struct multi_context *) arg;

  if (!version)
    multi_print_status (m, so, m->status_file_version);
  else
    multi_print_status (m, so, version);
}

static int
management_callback_kill_by_cn (void *arg, const char *del_cn)
{
  struct multi_context *m = (struct multi_context *) arg;
  struct hash_iterator hi;
  struct hash_element *he;
  int count = 0;

  hash_iterator_init (m->iter, &hi, true);
  while ((he = hash_iterator_next (&hi)))
    {
      struct multi_instance *mi = (struct multi_instance *) he->value;
      if (!mi->halt)
	{
	  const char *cn = tls_common_name (mi->context.c2.tls_multi, false);
	  if (cn && !strcmp (cn, del_cn))
	    {
	      multi_signal_instance (m, mi, SIGTERM);
	      ++count;
	    }
	}
    }
  hash_iterator_free (&hi);
  return count;
}

static int
management_callback_kill_by_addr (void *arg, const in_addr_t addr, const int port)
{
  struct multi_context *m = (struct multi_context *) arg;
  struct hash_iterator hi;
  struct hash_element *he;
  struct openvpn_sockaddr saddr;
  struct mroute_addr maddr;
  int count = 0;

  CLEAR (saddr);
  saddr.sa.sin_family = AF_INET;
  saddr.sa.sin_addr.s_addr = htonl (addr);
  saddr.sa.sin_port = htons (port);
  if (mroute_extract_openvpn_sockaddr (&maddr, &saddr, true))
    {
      hash_iterator_init (m->iter, &hi, true);
      while ((he = hash_iterator_next (&hi)))
	{
	  struct multi_instance *mi = (struct multi_instance *) he->value;
	  if (!mi->halt && mroute_addr_equal (&maddr, &mi->real))
	    {
	      multi_signal_instance (m, mi, SIGTERM);
	      ++count;
	    }
	}
      hash_iterator_free (&hi);
    }
  return count;
}

static void
management_delete_event (void *arg, event_t event)
{
  struct multi_context *m = (struct multi_context *) arg;
  if (m->mtcp)
    multi_tcp_delete_event (m->mtcp, event);
}

#endif

#ifdef MANAGEMENT_DEF_AUTH

static struct multi_instance *
lookup_by_cid (struct multi_context *m, const unsigned long cid)
{
  if (m)
    {
      struct multi_instance *mi = (struct multi_instance *) hash_lookup (m->cid_hash, &cid);
      if (mi && !mi->halt)
	return mi;
    }
  return NULL;
}

static bool
management_kill_by_cid (void *arg, const unsigned long cid)
{
  struct multi_context *m = (struct multi_context *) arg;
  struct multi_instance *mi = lookup_by_cid (m, cid);
  if (mi)
    {
      multi_signal_instance (m, mi, SIGTERM);
      return true;
    }
  else
    return false;
}

static bool
management_client_auth (void *arg,
			const unsigned long cid,
			const unsigned int mda_key_id,
			const bool auth,
			const char *reason,
			struct buffer_list *cc_config) /* ownership transferred */
{
  struct multi_context *m = (struct multi_context *) arg;
  struct multi_instance *mi = lookup_by_cid (m, cid);
  bool cc_config_owned = true;
  bool ret = false;

  if (mi)
    {
      ret = tls_authenticate_key (mi->context.c2.tls_multi, mda_key_id, auth);
      if (ret)
	{
	  if (auth && !mi->connection_established_flag)
	    {
	      set_cc_config (mi, cc_config);
	      cc_config_owned = false;
	    }
	  if (!auth && reason)
	    msg (D_MULTI_LOW, "MULTI: connection rejected: %s", reason);
	}
    }
  if (cc_config_owned && cc_config)
    buffer_list_free (cc_config);
  return ret;
}
#endif

#ifdef MANAGEMENT_PF
static bool
management_client_pf (void *arg,
		      const unsigned long cid,
		      struct buffer_list *pf_config) /* ownership transferred */
{
  struct multi_context *m = (struct multi_context *) arg;
  struct multi_instance *mi = lookup_by_cid (m, cid);
  bool ret = false;

  if (mi && pf_config)
    ret = pf_load_from_buffer_list (&mi->context, pf_config);

  if (pf_config)
    buffer_list_free (pf_config);
  return ret;
}
#endif

void
init_management_callback_multi (struct multi_context *m)
{
#ifdef ENABLE_MANAGEMENT
  if (management)
    {
      struct management_callback cb;
      CLEAR (cb);
      cb.arg = m;
      cb.status = management_callback_status;
      cb.show_net = management_show_net_callback;
      cb.kill_by_cn = management_callback_kill_by_cn;
      cb.kill_by_addr = management_callback_kill_by_addr;
      cb.delete_event = management_delete_event;
#ifdef MANAGEMENT_DEF_AUTH
      cb.kill_by_cid = management_kill_by_cid;
      cb.client_auth = management_client_auth;
#endif
#ifdef MANAGEMENT_PF
      cb.client_pf = management_client_pf;
#endif
      management_set_callback (management, &cb);
    }
#endif
}

void
uninit_management_callback_multi (struct multi_context *m)
{
  uninit_management_callback ();
}

/*
 * Top level event loop.
 */
void
tunnel_server (struct context *top)
{
  ASSERT (top->options.mode == MODE_SERVER);

  switch (top->options.ce.proto) {
  case PROTO_UDPv4:
    tunnel_server_udp (top);
    break;
  case PROTO_TCPv4_SERVER:
    tunnel_server_tcp (top);
    break;
  default:
    ASSERT (0);
  }
}

#else
static void dummy(void) {}
#endif /* P2MP_SERVER */