aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/pppol2tp.c
blob: 185b1dff10a8d572494c391aebf515133a56b2ff (plain) (blame)
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
/*****************************************************************************
 * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
 *
 * PPPoX    --- Generic PPP encapsulation socket family
 * PPPoL2TP --- PPP over L2TP (RFC 2661)
 *
 * Version:	1.0.0
 *
 * Authors:	Martijn van Oosterhout <kleptog@svana.org>
 *		James Chapman (jchapman@katalix.com)
 * Contributors:
 *		Michal Ostrowski <mostrows@speakeasy.net>
 *		Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
 *		David S. Miller (davem@redhat.com)
 *
 * License:
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 */

/* This driver handles only L2TP data frames; control frames are handled by a
 * userspace application.
 *
 * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
 * attaches it to a bound UDP socket with local tunnel_id / session_id and
 * peer tunnel_id / session_id set. Data can then be sent or received using
 * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
 * can be read or modified using ioctl() or [gs]etsockopt() calls.
 *
 * When a PPPoL2TP socket is connected with local and peer session_id values
 * zero, the socket is treated as a special tunnel management socket.
 *
 * Here's example userspace code to create a socket for sending/receiving data
 * over an L2TP session:-
 *
 *	struct sockaddr_pppol2tp sax;
 *	int fd;
 *	int session_fd;
 *
 *	fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
 *
 *	sax.sa_family = AF_PPPOX;
 *	sax.sa_protocol = PX_PROTO_OL2TP;
 *	sax.pppol2tp.fd = tunnel_fd;	// bound UDP socket
 *	sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
 *	sax.pppol2tp.addr.sin_port = addr->sin_port;
 *	sax.pppol2tp.addr.sin_family = AF_INET;
 *	sax.pppol2tp.s_tunnel  = tunnel_id;
 *	sax.pppol2tp.s_session = session_id;
 *	sax.pppol2tp.d_tunnel  = peer_tunnel_id;
 *	sax.pppol2tp.d_session = peer_session_id;
 *
 *	session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
 *
 * A pppd plugin that allows PPP traffic to be carried over L2TP using
 * this driver is available from the OpenL2TP project at
 * http://openl2tp.sourceforge.net.
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/list.h>
#include <asm/uaccess.h>

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/jiffies.h>

#include <linux/netdevice.h>
#include <linux/net.h>
#include <linux/inetdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/if_pppox.h>
#include <linux/if_pppol2tp.h>
#include <net/sock.h>
#include <linux/ppp_channel.h>
#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>
#include <linux/file.h>
#include <linux/hash.h>
#include <linux/sort.h>
#include <linux/proc_fs.h>
#include <net/net_namespace.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/xfrm.h>

#include <asm/byteorder.h>
#include <asm/atomic.h>


#define PPPOL2TP_DRV_VERSION	"V1.0"

/* L2TP header constants */
#define L2TP_HDRFLAG_T	   0x8000
#define L2TP_HDRFLAG_L	   0x4000
#define L2TP_HDRFLAG_S	   0x0800
#define L2TP_HDRFLAG_O	   0x0200
#define L2TP_HDRFLAG_P	   0x0100

#define L2TP_HDR_VER_MASK  0x000F
#define L2TP_HDR_VER	   0x0002

/* Space for UDP, L2TP and PPP headers */
#define PPPOL2TP_HEADER_OVERHEAD	40

/* Just some random numbers */
#define L2TP_TUNNEL_MAGIC	0x42114DDA
#define L2TP_SESSION_MAGIC	0x0C04EB7D

#define PPPOL2TP_HASH_BITS	4
#define PPPOL2TP_HASH_SIZE	(1 << PPPOL2TP_HASH_BITS)

/* Default trace flags */
#define PPPOL2TP_DEFAULT_DEBUG_FLAGS	0

#define PRINTK(_mask, _type, _lvl, _fmt, args...)			\
	do {								\
		if ((_mask) & (_type))					\
			printk(_lvl "PPPOL2TP: " _fmt, ##args);		\
	} while(0)

/* Number of bytes to build transmit L2TP headers.
 * Unfortunately the size is different depending on whether sequence numbers
 * are enabled.
 */
#define PPPOL2TP_L2TP_HDR_SIZE_SEQ		10
#define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ		6

struct pppol2tp_tunnel;

/* Describes a session. It is the sk_user_data field in the PPPoL2TP
 * socket. Contains information to determine incoming packets and transmit
 * outgoing ones.
 */
struct pppol2tp_session
{
	int			magic;		/* should be
						 * L2TP_SESSION_MAGIC */
	int			owner;		/* pid that opened the socket */

	struct sock		*sock;		/* Pointer to the session
						 * PPPoX socket */
	struct sock		*tunnel_sock;	/* Pointer to the tunnel UDP
						 * socket */

	struct pppol2tp_addr	tunnel_addr;	/* Description of tunnel */

	struct pppol2tp_tunnel	*tunnel;	/* back pointer to tunnel
						 * context */

	char			name[20];	/* "sess xxxxx/yyyyy", where
						 * x=tunnel_id, y=session_id */
	int			mtu;
	int			mru;
	int			flags;		/* accessed by PPPIOCGFLAGS.
						 * Unused. */
	unsigned		recv_seq:1;	/* expect receive packets with
						 * sequence numbers? */
	unsigned		send_seq:1;	/* send packets with sequence
						 * numbers? */
	unsigned		lns_mode:1;	/* behave as LNS? LAC enables
						 * sequence numbers under
						 * control of LNS. */
	int			debug;		/* bitmask of debug message
						 * categories */
	int			reorder_timeout; /* configured reorder timeout
						  * (in jiffies) */
	u16			nr;		/* session NR state (receive) */
	u16			ns;		/* session NR state (send) */
	struct sk_buff_head	reorder_q;	/* receive reorder queue */
	struct pppol2tp_ioc_stats stats;
	struct hlist_node	hlist;		/* Hash list node */
};

/* The sk_user_data field of the tunnel's UDP socket. It contains info to track
 * all the associated sessions so incoming packets can be sorted out
 */
struct pppol2tp_tunnel
{
	int			magic;		/* Should be L2TP_TUNNEL_MAGIC */
	rwlock_t		hlist_lock;	/* protect session_hlist */
	struct hlist_head	session_hlist[PPPOL2TP_HASH_SIZE];
						/* hashed list of sessions,
						 * hashed by id */
	int			debug;		/* bitmask of debug message
						 * categories */
	char			name[12];	/* "tunl xxxxx" */
	struct pppol2tp_ioc_stats stats;

	void (*old_sk_destruct)(struct sock *);

	struct sock		*sock;		/* Parent socket */
	struct list_head	list;		/* Keep a list of all open
						 * prepared sockets */

	atomic_t		ref_count;
};

/* Private data stored for received packets in the skb.
 */
struct pppol2tp_skb_cb {
	u16			ns;
	u16			nr;
	u16			has_seq;
	u16			length;
	unsigned long		expires;
};

#define PPPOL2TP_SKB_CB(skb)	((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])

static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel);

static atomic_t pppol2tp_tunnel_count;
static atomic_t pppol2tp_session_count;
static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
static struct proto_ops pppol2tp_ops;
static LIST_HEAD(pppol2tp_tunnel_list);
static DEFINE_RWLOCK(pppol2tp_tunnel_list_lock);

/* Helpers to obtain tunnel/session contexts from sockets.
 */
static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
{
	struct pppol2tp_session *session;

	if (sk == NULL)
		return NULL;

	sock_hold(sk);
	session = (struct pppol2tp_session *)(sk->sk_user_data);
	if (session == NULL) {
		sock_put(sk);
		goto out;
	}

	BUG_ON(session->magic != L2TP_SESSION_MAGIC);
out:
	return session;
}

static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
{
	struct pppol2tp_tunnel *tunnel;

	if (sk == NULL)
		return NULL;

	sock_hold(sk);
	tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
	if (tunnel == NULL) {
		sock_put(sk);
		goto out;
	}

	BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
out:
	return tunnel;
}

/* Tunnel reference counts. Incremented per session that is added to
 * the tunnel.
 */
static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel)
{
	atomic_inc(&tunnel->ref_count);
}

static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel)
{
	if (atomic_dec_and_test(&tunnel->ref_count))
		pppol2tp_tunnel_free(tunnel);
}

/* Session hash list.
 * The session_id SHOULD be random according to RFC2661, but several
 * L2TP implementations (Cisco and Microsoft) use incrementing
 * session_ids.  So we do a real hash on the session_id, rather than a
 * simple bitmask.
 */
static inline struct hlist_head *
pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id)
{
	unsigned long hash_val = (unsigned long) session_id;
	return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)];
}

/* Lookup a session by id
 */
static struct pppol2tp_session *
pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id)
{
	struct hlist_head *session_list =
		pppol2tp_session_id_hash(tunnel, session_id);
	struct pppol2tp_session *session;
	struct hlist_node *walk;

	read_lock_bh(&tunnel->hlist_lock);
	hlist_for_each_entry(session, walk, session_list, hlist) {
		if (session->tunnel_addr.s_session == session_id) {
			read_unlock_bh(&tunnel->hlist_lock);
			return session;
		}
	}
	read_unlock_bh(&tunnel->hlist_lock);

	return NULL;
}

/* Lookup a tunnel by id
 */
static struct pppol2tp_tunnel *pppol2tp_tunnel_find(u16 tunnel_id)
{
	struct pppol2tp_tunnel *tunnel = NULL;

	read_lock_bh(&pppol2tp_tunnel_list_lock);
	list_for_each_entry(tunnel, &pppol2tp_tunnel_list, list) {
		if (tunnel->stats.tunnel_id == tunnel_id) {
			read_unlock_bh(&pppol2tp_tunnel_list_lock);
			return tunnel;
		}
	}
	read_unlock_bh(&pppol2tp_tunnel_list_lock);

	return NULL;
}

/*****************************************************************************
 * Receive data handling
 *****************************************************************************/

/* Queue a skb in order. We come here only if the skb has an L2TP sequence
 * number.
 */
static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
{
	struct sk_buff *skbp;
	struct sk_buff *tmp;
	u16 ns = PPPOL2TP_SKB_CB(skb)->ns;

	spin_lock_bh(&session->reorder_q.lock);
	skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
		if (PPPOL2TP_SKB_CB(skbp)->ns > ns) {
			__skb_queue_before(&session->reorder_q, skbp, skb);
			PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
			       "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
			       session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns,
			       skb_queue_len(&session->reorder_q));
			session->stats.rx_oos_packets++;
			goto out;
		}
	}

	__skb_queue_tail(&session->reorder_q, skb);

out:
	spin_unlock_bh(&session->reorder_q.lock);
}

/* Dequeue a single skb.
 */
static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
{
	struct pppol2tp_tunnel *tunnel = session->tunnel;
	int length = PPPOL2TP_SKB_CB(skb)->length;
	struct sock *session_sock = NULL;

	/* We're about to requeue the skb, so return resources
	 * to its current owner (a socket receive buffer).
	 */
	skb_orphan(skb);

	tunnel->stats.rx_packets++;
	tunnel->stats.rx_bytes += length;
	session->stats.rx_packets++;
	session->stats.rx_bytes += length;

	if (PPPOL2TP_SKB_CB(skb)->has_seq) {
		/* Bump our Nr */
		session->nr++;
		PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
		       "%s: updated nr to %hu\n", session->name, session->nr);
	}

	/* If the socket is bound, send it in to PPP's input queue. Otherwise
	 * queue it on the session socket.
	 */
	session_sock = session->sock;
	if (session_sock->sk_state & PPPOX_BOUND) {
		struct pppox_sock *po;
		PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
		       "%s: recv %d byte data frame, passing to ppp\n",
		       session->name, length);

		/* We need to forget all info related to the L2TP packet
		 * gathered in the skb as we are going to reuse the same
		 * skb for the inner packet.
		 * Namely we need to:
		 * - reset xfrm (IPSec) information as it applies to
		 *   the outer L2TP packet and not to the inner one
		 * - release the dst to force a route lookup on the inner
		 *   IP packet since skb->dst currently points to the dst
		 *   of the UDP tunnel
		 * - reset netfilter information as it doesn't apply
		 *   to the inner packet either
		 */
		secpath_reset(skb);
		dst_release(skb->dst);
		skb->dst = NULL;
		nf_reset(skb);

		po = pppox_sk(session_sock);
		ppp_input(&po->chan, skb);
	} else {
		PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
		       "%s: socket not bound\n", session->name);

		/* Not bound. Nothing we can do, so discard. */
		session->stats.rx_errors++;
		kfree_skb(skb);
	}

	sock_put(session->sock);
}

/* Dequeue skbs from the session's reorder_q, subject to packet order.
 * Skbs that have been in the queue for too long are simply discarded.
 */
static void pppol2tp_recv_dequeue(struct pppol2tp_session *session)
{
	struct sk_buff *skb;
	struct sk_buff *tmp;

	/* If the pkt at the head of the queue has the nr that we
	 * expect to send up next, dequeue it and any other
	 * in-sequence packets behind it.
	 */
	spin_lock_bh(&session->reorder_q.lock);
	skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
		if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) {
			session->stats.rx_seq_discards++;
			session->stats.rx_errors++;
			PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
			       "%s: oos pkt %hu len %d discarded (too old), "
			       "waiting for %hu, reorder_q_len=%d\n",
			       session->name, PPPOL2TP_SKB_CB(skb)->ns,
			       PPPOL2TP_SKB_CB(skb)->length, session->nr,
			       skb_queue_len(&session->reorder_q));
			__skb_unlink(skb, &session->reorder_q);
			kfree_skb(skb);
			sock_put(session->sock);
			continue;
		}

		if (PPPOL2TP_SKB_CB(skb)->has_seq) {
			if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
				PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
				       "%s: holding oos pkt %hu len %d, "
				       "waiting for %hu, reorder_q_len=%d\n",
				       session->name, PPPOL2TP_SKB_CB(skb)->ns,
				       PPPOL2TP_SKB_CB(skb)->length, session->nr,
				       skb_queue_len(&session->reorder_q));
				goto out;
			}
		}
		__skb_unlink(skb, &session->reorder_q);

		/* Process the skb. We release the queue lock while we
		 * do so to let other contexts process the queue.
		 */
		spin_unlock_bh(&session->reorder_q.lock);
		pppol2tp_recv_dequeue_skb(session, skb);
		spin_lock_bh(&session->reorder_q.lock);
	}

out:
	spin_unlock_bh(&session->reorder_q.lock);
}

/* Internal receive frame. Do the real work of receiving an L2TP data frame
 * here. The skb is not on a list when we get here.
 * Returns 0 if the packet was a data packet and was successfully passed on.
 * Returns 1 if the packet was not a good data packet and could not be
 * forwarded.  All such packets are passed up to userspace to deal with.
 */
static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
{
	struct pppol2tp_session *session = NULL;
	struct pppol2tp_tunnel *tunnel;
	unsigned char *ptr, *optr;
	u16 hdrflags;
	u16 tunnel_id, session_id;
	int length;
	int offset;

	tunnel = pppol2tp_sock_to_tunnel(sock);
	if (tunnel == NULL)
		goto no_tunnel;

	/* UDP always verifies the packet length. */
	__skb_pull(skb, sizeof(struct udphdr));

	/* Short packet? */
	if (!pskb_may_pull(skb, 12)) {
		PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
		       "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
		goto error;
	}

	/* Point to L2TP header */
	optr = ptr = skb->data;

	/* Get L2TP header flags */
	hdrflags = ntohs(*(__be16*)ptr);

	/* Trace packet contents, if enabled */
	if (tunnel->debug & PPPOL2TP_MSG_DATA) {
		length = min(16u, skb->len);
		if (!pskb_may_pull(skb, length))
			goto error;

		printk(KERN_DEBUG "%s: recv: ", tunnel->name);

		offset = 0;
		do {
			printk(" %02X", ptr[offset]);
		} while (++offset < length);

		printk("\n");
	}

	/* Get length of L2TP packet */
	length = skb->len;

	/* If type is control packet, it is handled by userspace. */
	if (hdrflags & L2TP_HDRFLAG_T) {
		PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
		       "%s: recv control packet, len=%d\n", tunnel->name, length);
		goto error;
	}

	/* Skip flags */
	ptr += 2;

	/* If length is present, skip it */
	if (hdrflags & L2TP_HDRFLAG_L)
		ptr += 2;

	/* Extract tunnel and session ID */
	tunnel_id = ntohs(*(__be16 *) ptr);
	ptr += 2;
	session_id = ntohs(*(__be16 *) ptr);
	ptr += 2;

	/* Find the session context */
	session = pppol2tp_session_find(tunnel, session_id);
	if (!session) {
		/* Not found? Pass to userspace to deal with */
		PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
		       "%s: no socket found (%hu/%hu). Passing up.\n",
		       tunnel->name, tunnel_id, session_id);
		goto error;
	}
	sock_hold(session->sock);

	/* The ref count on the socket was increased by the above call since
	 * we now hold a pointer to the session. Take care to do sock_put()
	 * when exiting this function from now on...
	 */

	/* Handle the optional sequence numbers.  If we are the LAC,
	 * enable/disable sequence numbers under the control of the LNS.  If
	 * no sequence numbers present but we were expecting them, discard
	 * frame.
	 */
	if (hdrflags & L2TP_HDRFLAG_S) {
		u16 ns, nr;
		ns = ntohs(*(__be16 *) ptr);
		ptr += 2;
		nr = ntohs(*(__be16 *) ptr);
		ptr += 2;

		/* Received a packet with sequence numbers. If we're the LNS,
		 * check if we sre sending sequence numbers and if not,
		 * configure it so.
		 */
		if ((!session->lns_mode) && (!session->send_seq)) {
			PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
			       "%s: requested to enable seq numbers by LNS\n",
			       session->name);
			session->send_seq = -1;
		}

		/* Store L2TP info in the skb */
		PPPOL2TP_SKB_CB(skb)->ns = ns;
		PPPOL2TP_SKB_CB(skb)->nr = nr;
		PPPOL2TP_SKB_CB(skb)->has_seq = 1;

		PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
		       "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n",
		       session->name, ns, nr, session->nr);
	} else {
		/* No sequence numbers.
		 * If user has configured mandatory sequence numbers, discard.
		 */
		if (session->recv_seq) {
			PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
			       "%s: recv data has no seq numbers when required. "
			       "Discarding\n", session->name);
			session->stats.rx_seq_discards++;
			goto discard;
		}

		/* If we're the LAC and we're sending sequence numbers, the
		 * LNS has requested that we no longer send sequence numbers.
		 * If we're the LNS and we're sending sequence numbers, the
		 * LAC is broken. Discard the frame.
		 */
		if ((!session->lns_mode) && (session->send_seq)) {
			PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
			       "%s: requested to disable seq numbers by LNS\n",
			       session->name);
			session->send_seq = 0;
		} else if (session->send_seq) {
			PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
			       "%s: recv data has no seq numbers when required. "
			       "Discarding\n", session->name);
			session->stats.rx_seq_discards++;
			goto discard;
		}

		/* Store L2TP info in the skb */
		PPPOL2TP_SKB_CB(skb)->has_seq = 0;
	}

	/* If offset bit set, skip it. */
	if (hdrflags & L2TP_HDRFLAG_O) {
		offset = ntohs(*(__be16 *)ptr);
		ptr += 2 + offset;
	}

	offset = ptr - optr;
	if (!pskb_may_pull(skb, offset))
		goto discard;

	__skb_pull(skb, offset);

	/* Skip PPP header, if present.	 In testing, Microsoft L2TP clients
	 * don't send the PPP header (PPP header compression enabled), but
	 * other clients can include the header. So we cope with both cases
	 * here. The PPP header is always FF03 when using L2TP.
	 *
	 * Note that skb->data[] isn't dereferenced from a u16 ptr here since
	 * the field may be unaligned.
	 */
	if (!pskb_may_pull(skb, 2))
		goto discard;

	if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
		skb_pull(skb, 2);

	/* Prepare skb for adding to the session's reorder_q.  Hold
	 * packets for max reorder_timeout or 1 second if not
	 * reordering.
	 */
	PPPOL2TP_SKB_CB(skb)->length = length;
	PPPOL2TP_SKB_CB(skb)->expires = jiffies +
		(session->reorder_timeout ? session->reorder_timeout : HZ);

	/* Add packet to the session's receive queue. Reordering is done here, if
	 * enabled. Saved L2TP protocol info is stored in skb->sb[].
	 */
	if (PPPOL2TP_SKB_CB(skb)->has_seq) {
		if (session->reorder_timeout != 0) {
			/* Packet reordering enabled. Add skb to session's
			 * reorder queue, in order of ns.
			 */
			pppol2tp_recv_queue_skb(session, skb);
		} else {
			/* Packet reordering disabled. Discard out-of-sequence
			 * packets
			 */
			if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
				session->stats.rx_seq_discards++;
				PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
				       "%s: oos pkt %hu len %d discarded, "
				       "waiting for %hu, reorder_q_len=%d\n",
				       session->name, PPPOL2TP_SKB_CB(skb)->ns,
				       PPPOL2TP_SKB_CB(skb)->length, session->nr,
				       skb_queue_len(&session->reorder_q));
				goto discard;
			}
			skb_queue_tail(&session->reorder_q, skb);
		}
	} else {
		/* No sequence numbers. Add the skb to the tail of the
		 * reorder queue. This ensures that it will be
		 * delivered after all previous sequenced skbs.
		 */
		skb_queue_tail(&session->reorder_q, skb);
	}

	/* Try to dequeue as many skbs from reorder_q as we can. */
	pppol2tp_recv_dequeue(session);

	return 0;

discard:
	session->stats.rx_errors++;
	kfree_skb(skb);
	sock_put(session->sock);
	sock_put(sock);

	return 0;

error:
	/* Put UDP header back */
	__skb_push(skb, sizeof(struct udphdr));
	sock_put(sock);

no_tunnel:
	return 1;
}

/* UDP encapsulation receive handler. See net/ipv4/udp.c.
 * Return codes:
 * 0 : success.
 * <0: error
 * >0: skb should be passed up to userspace as UDP.
 */
static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
{
	struct pppol2tp_tunnel *tunnel;

	tunnel = pppol2tp_sock_to_tunnel(sk);
	if (tunnel == NULL)
		goto pass_up;

	PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
	       "%s: received %d bytes\n", tunnel->name, skb->len);

	if (pppol2tp_recv_core(sk, skb))
		goto pass_up_put;

	sock_put(sk);
	return 0;

pass_up_put:
	sock_put(sk);
pass_up:
	return 1;
}

/* Receive message. This is the recvmsg for the PPPoL2TP socket.
 */
static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
			    struct msghdr *msg, size_t len,
			    int flags)
{
	int err;
	struct sk_buff *skb;
	struct sock *sk = sock->sk;

	err = -EIO;
	if (sk->sk_state & PPPOX_BOUND)
		goto end;

	msg->msg_namelen = 0;

	err = 0;
	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
				flags & MSG_DONTWAIT, &err);
	if (!skb)
		goto end;

	if (len > skb->len)
		len = skb->len;
	else if (len < skb->len)
		msg->msg_flags |= MSG_TRUNC;

	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
	if (likely(err == 0))
		err = len;

	kfree_skb(skb);
end:
	return err;
}

/************************************************************************
 * Transmit handling
 ***********************************************************************/

/* Tell how big L2TP headers are for a particular session. This
 * depends on whether sequence numbers are being used.
 */
static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
{
	if (session->send_seq)
		return PPPOL2TP_L2TP_HDR_SIZE_SEQ;

	return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
}

/* Build an L2TP header for the session into the buffer provided.
 */
static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
				       void *buf)
{
	__be16 *bufp = buf;
	u16 flags = L2TP_HDR_VER;

	if (session->send_seq)
		flags |= L2TP_HDRFLAG_S;

	/* Setup L2TP header.
	 * FIXME: Can this ever be unaligned? Is direct dereferencing of
	 * 16-bit header fields safe here for all architectures?
	 */
	*bufp++ = htons(flags);
	*bufp++ = htons(session->tunnel_addr.d_tunnel);
	*bufp++ = htons(session->tunnel_addr.d_session);
	if (session->send_seq) {
		*bufp++ = htons(session->ns);
		*bufp++ = 0;
		session->ns++;
		PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
		       "%s: updated ns to %hu\n", session->name, session->ns);
	}
}

/* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 * when a user application does a sendmsg() on the session socket. L2TP and
 * PPP headers must be inserted into the user's data.
 */
static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
			    size_t total_len)
{
	static const unsigned char ppph[2] = { 0xff, 0x03 };
	struct sock *sk = sock->sk;
	struct inet_sock *inet;
	__wsum csum = 0;
	struct sk_buff *skb;
	int error;
	int hdr_len;
	struct pppol2tp_session *session;
	struct pppol2tp_tunnel *tunnel;
	struct udphdr *uh;
	unsigned int len;

	error = -ENOTCONN;
	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
		goto error;

	/* Get session and tunnel contexts */
	error = -EBADF;
	session = pppol2tp_sock_to_session(sk);
	if (session == NULL)
		goto error;

	tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
	if (tunnel == NULL)
		goto error_put_sess;

	/* What header length is configured for this session? */
	hdr_len = pppol2tp_l2tp_header_len(session);

	/* Allocate a socket buffer */
	error = -ENOMEM;
	skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
			   sizeof(struct udphdr) + hdr_len +
			   sizeof(ppph) + total_len,
			   0, GFP_KERNEL);
	if (!skb)
		goto error_put_sess_tun;

	/* Reserve space for headers. */
	skb_reserve(skb, NET_SKB_PAD);
	skb_reset_network_header(skb);
	skb_reserve(skb, sizeof(struct iphdr));
	skb_reset_transport_header(skb);

	/* Build UDP header */
	inet = inet_sk(session->tunnel_sock);
	uh = (struct udphdr *) skb->data;
	uh->source = inet->sport;
	uh->dest = inet->dport;
	uh->len = htons(hdr_len + sizeof(ppph) + total_len);
	uh->check = 0;
	skb_put(skb, sizeof(struct udphdr));

	/* Build L2TP header */
	pppol2tp_build_l2tp_header(session, skb->data);
	skb_put(skb, hdr_len);

	/* Add PPP header */
	skb->data[0] = ppph[0];
	skb->data[1] = ppph[1];
	skb_put(skb, 2);

	/* Copy user data into skb */
	error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
	if (error < 0) {
		kfree_skb(skb);
		goto error_put_sess_tun;
	}
	skb_put(skb, total_len);

	/* Calculate UDP checksum if configured to do so */
	if (session->tunnel_sock->sk_no_check != UDP_CSUM_NOXMIT)
		csum = udp_csum_outgoing(sk, skb);

	/* Debug */
	if (session->send_seq)
		PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
		       "%s: send %Zd bytes, ns=%hu\n", session->name,
		       total_len, session->ns - 1);
	else
		PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
		       "%s: send %Zd bytes\n", session->name, total_len);

	if (session->debug & PPPOL2TP_MSG_DATA) {
		int i;
		unsigned char *datap = skb->data;

		printk(KERN_DEBUG "%s: xmit:", session->name);
		for (i = 0; i < total_len; i++) {
			printk(" %02X", *datap++);
			if (i == 15) {
				printk(" ...");
				break;
			}
		}
		printk("\n");
	}

	/* Queue the packet to IP for output */
	len = skb->len;
	error = ip_queue_xmit(skb, 1);

	/* Update stats */
	if (error >= 0) {
		tunnel->stats.tx_packets++;
		tunnel->stats.tx_bytes += len;
		session->stats.tx_packets++;
		session->stats.tx_bytes += len;
	} else {
		tunnel->stats.tx_errors++;
		session->stats.tx_errors++;
	}

	return error;

error_put_sess_tun:
	sock_put(session->tunnel_sock);
error_put_sess:
	sock_put(sk);
error:
	return error;
}

/* Automatically called when the skb is freed.
 */
static void pppol2tp_sock_wfree(struct sk_buff *skb)
{
	sock_put(skb->sk);
}

/* For data skbs that we transmit, we associate with the tunnel socket
 * but don't do accounting.
 */
static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
{
	sock_hold(sk);
	skb->sk = sk;
	skb->destructor = pppol2tp_sock_wfree;
}

/* Transmit function called by generic PPP driver.  Sends PPP frame
 * over PPPoL2TP socket.
 *
 * This is almost the same as pppol2tp_sendmsg(), but rather than
 * being called with a msghdr from userspace, it is called with a skb
 * from the kernel.
 *
 * The supplied skb from ppp doesn't have enough headroom for the
 * insertion of L2TP, UDP and IP headers so we need to allocate more
 * headroom in the skb. This will create a cloned skb. But we must be
 * careful in the error case because the caller will expect to free
 * the skb it supplied, not our cloned skb. So we take care to always
 * leave the original skb unfreed if we return an error.
 */
static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
{
	static const u8 ppph[2] = { 0xff, 0x03 };
	struct sock *sk = (struct sock *) chan->private;
	struct sock *sk_tun;
	int hdr_len;
	struct pppol2tp_session *session;
	struct pppol2tp_tunnel *tunnel;
	int rc;
	int headroom;
	int data_len = skb->len;
	struct inet_sock *inet;
	__wsum csum = 0;
	struct udphdr *uh;
	unsigned int len;
	int old_headroom;
	int new_headroom;

	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
		goto abort;

	/* Get session and tunnel contexts from the socket */
	session = pppol2tp_sock_to_session(sk);
	if (session == NULL)
		goto abort;

	sk_tun = session->tunnel_sock;
	if (sk_tun == NULL)
		goto abort_put_sess;
	tunnel = pppol2tp_sock_to_tunnel(sk_tun);
	if (tunnel == NULL)
		goto abort_put_sess;

	/* What header length is configured for this session? */
	hdr_len = pppol2tp_l2tp_header_len(session);

	/* Check that there's enough headroom in the skb to insert IP,
	 * UDP and L2TP and PPP headers. If not enough, expand it to
	 * make room. Adjust truesize.
	 */
	headroom = NET_SKB_PAD + sizeof(struct iphdr) +
		sizeof(struct udphdr) + hdr_len + sizeof(ppph);
	old_headroom = skb_headroom(skb);
	if (skb_cow_head(skb, headroom))
		goto abort_put_sess_tun;

	new_headroom = skb_headroom(skb);
	skb_orphan(skb);
	skb->truesize += new_headroom - old_headroom;

	/* Setup PPP header */
	__skb_push(skb, sizeof(ppph));
	skb->data[0] = ppph[0];
	skb->data[1] = ppph[1];

	/* Setup L2TP header */
	pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));

	/* Setup UDP header */
	inet = inet_sk(sk_tun);
	__skb_push(skb, sizeof(*uh));
	skb_reset_transport_header(skb);
	uh = udp_hdr(skb);
	uh->source = inet->sport;
	uh->dest = inet->dport;
	uh->len = htons(sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len);
	uh->check = 0;

	/* *BROKEN* Calculate UDP checksum if configured to do so */
	if (sk_tun->sk_no_check != UDP_CSUM_NOXMIT)
		csum = udp_csum_outgoing(sk_tun, skb);

	/* Debug */
	if (session->send_seq)
		PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
		       "%s: send %d bytes, ns=%hu\n", session->name,
		       data_len, session->ns - 1);
	else
		PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
		       "%s: send %d bytes\n", session->name, data_len);

	if (session->debug & PPPOL2TP_MSG_DATA) {
		int i;
		unsigned char *datap = skb->data;

		printk(KERN_DEBUG "%s: xmit:", session->name);
		for (i = 0; i < data_len; i++) {
			printk(" %02X", *datap++);
			if (i == 31) {
				printk(" ...");
				break;
			}
		}
		printk("\n");
	}

	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
			      IPSKB_REROUTED);
	nf_reset(skb);

	/* Get routing info from the tunnel socket */
	dst_release(skb->dst);
	skb->dst = dst_clone(__sk_dst_get(sk_tun));
	pppol2tp_skb_set_owner_w(skb, sk_tun);

	/* Queue the packet to IP for output */
	len = skb->len;
	rc = ip_queue_xmit(skb, 1);

	/* Update stats */
	if (rc >= 0) {
		tunnel->stats.tx_packets++;
		tunnel->stats.tx_bytes += len;
		session->stats.tx_packets++;
		session->stats.tx_bytes += len;
	} else {
		tunnel->stats.tx_errors++;
		session->stats.tx_errors++;
	}

	sock_put(sk_tun);
	sock_put(sk);
	return 1;

abort_put_sess_tun:
	sock_put(sk_tun);
abort_put_sess:
	sock_put(sk);
abort:
	/* Free the original skb */
	kfree_skb(skb);
	return 1;
}

/*****************************************************************************
 * Session (and tunnel control) socket create/destroy.
 *****************************************************************************/

/* When the tunnel UDP socket is closed, all the attached sockets need to go
 * too.
 */
static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
{
	int hash;
	struct hlist_node *walk;
	struct hlist_node *tmp;
	struct pppol2tp_session *session;
	struct sock *sk;

	if (tunnel == NULL)
		BUG();

	PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
	       "%s: closing all sessions...\n", tunnel->name);

	write_lock_bh(&tunnel->hlist_lock);
	for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
again:
		hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
			struct sk_buff *skb;

			session = hlist_entry(walk, struct pppol2tp_session, hlist);

			sk = session->sock;

			PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
			       "%s: closing session\n", session->name);

			hlist_del_init(&session->hlist);

			/* Since we should hold the sock lock while
			 * doing any unbinding, we need to release the
			 * lock we're holding before taking that lock.
			 * Hold a reference to the sock so it doesn't
			 * disappear as we're jumping between locks.
			 */
			sock_hold(sk);
			write_unlock_bh(&tunnel->hlist_lock);
			lock_sock(sk);

			if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
				pppox_unbind_sock(sk);
				sk->sk_state = PPPOX_DEAD;
				sk->sk_state_change(sk);
			}

			/* Purge any queued data */
			skb_queue_purge(&sk->sk_receive_queue);
			skb_queue_purge(&sk->sk_write_queue);
			while ((skb = skb_dequeue(&session->reorder_q))) {
				kfree_skb(skb);
				sock_put(sk);
			}

			release_sock(sk);
			sock_put(sk);

			/* Now restart from the beginning of this hash
			 * chain.  We always remove a session from the
			 * list so we are guaranteed to make forward
			 * progress.
			 */
			write_lock_bh(&tunnel->hlist_lock);
			goto again;
		}
	}
	write_unlock_bh(&tunnel->hlist_lock);
}

/* Really kill the tunnel.
 * Come here only when all sessions have been cleared from the tunnel.
 */
static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
{
	/* Remove from socket list */
	write_lock_bh(&pppol2tp_tunnel_list_lock);
	list_del_init(&tunnel->list);
	write_unlock_bh(&pppol2tp_tunnel_list_lock);

	atomic_dec(&pppol2tp_tunnel_count);
	kfree(tunnel);
}

/* Tunnel UDP socket destruct hook.
 * The tunnel context is deleted only when all session sockets have been
 * closed.
 */
static void pppol2tp_tunnel_destruct(struct sock *sk)
{
	struct pppol2tp_tunnel *tunnel;

	tunnel = sk->sk_user_data;
	if (tunnel == NULL)
		goto end;

	PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
	       "%s: closing...\n", tunnel->name);

	/* Close all sessions */
	pppol2tp_tunnel_closeall(tunnel);

	/* No longer an encapsulation socket. See net/ipv4/udp.c */
	(udp_sk(sk))->encap_type = 0;
	(udp_sk(sk))->encap_rcv = NULL;

	/* Remove hooks into tunnel socket */
	tunnel->sock = NULL;
	sk->sk_destruct = tunnel->old_sk_destruct;
	sk->sk_user_data = NULL;

	/* Call original (UDP) socket descructor */
	if (sk->sk_destruct != NULL)
		(*sk->sk_destruct)(sk);

	pppol2tp_tunnel_dec_refcount(tunnel);

end:
	return;
}

/* Really kill the session socket. (Called from sock_put() if
 * refcnt == 0.)
 */
static void pppol2tp_session_destruct(struct sock *sk)
{
	struct pppol2tp_session *session = NULL;

	if (sk->sk_user_data != NULL) {
		struct pppol2tp_tunnel *tunnel;

		session = sk->sk_user_data;
		if (session == NULL)
			goto out;

		BUG_ON(session->magic != L2TP_SESSION_MAGIC);

		/* Don't use pppol2tp_sock_to_tunnel() here to
		 * get the tunnel context because the tunnel
		 * socket might have already been closed (its
		 * sk->sk_user_data will be NULL) so use the
		 * session's private tunnel ptr instead.
		 */
		tunnel = session->tunnel;
		if (tunnel != NULL) {
			BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);

			/* If session_id is zero, this is a null
			 * session context, which was created for a
			 * socket that is being used only to manage
			 * tunnels.
			 */
			if (session->tunnel_addr.s_session != 0) {
				/* Delete the session socket from the
				 * hash
				 */
				write_lock_bh(&tunnel->hlist_lock);
				hlist_del_init(&session->hlist);
				write_unlock_bh(&tunnel->hlist_lock);

				atomic_dec(&pppol2tp_session_count);
			}

			/* This will delete the tunnel context if this
			 * is the last session on the tunnel.
			 */
			session->tunnel = NULL;
			session->tunnel_sock = NULL;
			pppol2tp_tunnel_dec_refcount(tunnel);
		}
	}

	kfree(session);
out:
	return;
}

/* Called when the PPPoX socket (session) is closed.
 */
static int pppol2tp_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	struct pppol2tp_session *session;
	int error;

	if (!sk)
		return 0;

	error = -EBADF;
	lock_sock(sk);
	if (sock_flag(sk, SOCK_DEAD) != 0)
		goto error;

	pppox_unbind_sock(sk);

	/* Signal the death of the socket. */
	sk->sk_state = PPPOX_DEAD;
	sock_orphan(sk);
	sock->sk = NULL;

	session = pppol2tp_sock_to_session(sk);

	/* Purge any queued data */
	skb_queue_purge(&sk->sk_receive_queue);
	skb_queue_purge(&sk->sk_write_queue);
	if (session != NULL) {
		struct sk_buff *skb;
		while ((skb = skb_dequeue(&session->reorder_q))) {
			kfree_skb(skb);
			sock_put(sk);
		}
	}

	release_sock(sk);

	/* This will delete the session context via
	 * pppol2tp_session_destruct() if the socket's refcnt drops to
	 * zero.
	 */
	sock_put(sk);

	return 0;

error:
	release_sock(sk);
	return error;
}

/* Internal function to prepare a tunnel (UDP) socket to have PPPoX
 * sockets attached to it.
 */
static struct sock *pppol2tp_prepare_tunnel_socket(int fd, u16 tunnel_id,
						   int *error)
{
	int err;
	struct socket *sock = NULL;
	struct sock *sk;
	struct pppol2tp_tunnel *tunnel;
	struct sock *ret = NULL;

	/* Get the tunnel UDP socket from the fd, which was opened by
	 * the userspace L2TP daemon.
	 */
	err = -EBADF;
	sock = sockfd_lookup(fd, &err);
	if (!sock) {
		PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
		       "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
		       tunnel_id, fd, err);
		goto err;
	}

	sk = sock->sk;

	/* Quick sanity checks */
	err = -EPROTONOSUPPORT;
	if (sk->sk_protocol != IPPROTO_UDP) {
		PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
		       "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
		       tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
		goto err;
	}
	err = -EAFNOSUPPORT;
	if (sock->ops->family != AF_INET) {
		PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
		       "tunl %hu: fd %d wrong family, got %d, expected %d\n",
		       tunnel_id, fd, sock->ops->family, AF_INET);
		goto err;
	}

	err = -ENOTCONN;

	/* Check if this socket has already been prepped */
	tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
	if (tunnel != NULL) {
		/* User-data field already set */
		err = -EBUSY;
		BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);

		/* This socket has already been prepped */
		ret = tunnel->sock;
		goto out;
	}

	/* This socket is available and needs prepping. Create a new tunnel
	 * context and init it.
	 */
	sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
	if (sk->sk_user_data == NULL) {
		err = -ENOMEM;
		goto err;
	}

	tunnel->magic = L2TP_TUNNEL_MAGIC;
	sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);

	tunnel->stats.tunnel_id = tunnel_id;
	tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;

	/* Hook on the tunnel socket destructor so that we can cleanup
	 * if the tunnel socket goes away.
	 */
	tunnel->old_sk_destruct = sk->sk_destruct;
	sk->sk_destruct = &pppol2tp_tunnel_destruct;

	tunnel->sock = sk;
	sk->sk_allocation = GFP_ATOMIC;

	/* Misc init */
	rwlock_init(&tunnel->hlist_lock);

	/* Add tunnel to our list */
	INIT_LIST_HEAD(&tunnel->list);
	write_lock_bh(&pppol2tp_tunnel_list_lock);
	list_add(&tunnel->list, &pppol2tp_tunnel_list);
	write_unlock_bh(&pppol2tp_tunnel_list_lock);
	atomic_inc(&pppol2tp_tunnel_count);

	/* Bump the reference count. The tunnel context is deleted
	 * only when this drops to zero.
	 */
	pppol2tp_tunnel_inc_refcount(tunnel);

	/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
	(udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
	(udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;

	ret = tunnel->sock;

	*error = 0;
out:
	if (sock)
		sockfd_put(sock);

	return ret;

err:
	*error = err;
	goto out;
}

static struct proto pppol2tp_sk_proto = {
	.name	  = "PPPOL2TP",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct pppox_sock),
};

/* socket() handler. Initialize a new struct sock.
 */
static int pppol2tp_create(struct net *net, struct socket *sock)
{
	int error = -ENOMEM;
	struct sock *sk;

	sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
	if (!sk)
		goto out;

	sock_init_data(sock, sk);

	sock->state  = SS_UNCONNECTED;
	sock->ops    = &pppol2tp_ops;

	sk->sk_backlog_rcv = pppol2tp_recv_core;
	sk->sk_protocol	   = PX_PROTO_OL2TP;
	sk->sk_family	   = PF_PPPOX;
	sk->sk_state	   = PPPOX_NONE;
	sk->sk_type	   = SOCK_STREAM;
	sk->sk_destruct	   = pppol2tp_session_destruct;

	error = 0;

out:
	return error;
}

/* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
 */
static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
			    int sockaddr_len, int flags)
{
	struct sock *sk = sock->sk;
	struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
	struct pppox_sock *po = pppox_sk(sk);
	struct sock *tunnel_sock = NULL;
	struct pppol2tp_session *session = NULL;
	struct pppol2tp_tunnel *tunnel;
	struct dst_entry *dst;
	int error = 0;

	lock_sock(sk);

	error = -EINVAL;
	if (sp->sa_protocol != PX_PROTO_OL2TP)
		goto end;

	/* Check for already bound sockets */
	error = -EBUSY;
	if (sk->sk_state & PPPOX_CONNECTED)
		goto end;

	/* We don't supporting rebinding anyway */
	error = -EALREADY;
	if (sk->sk_user_data)
		goto end; /* socket is already attached */

	/* Don't bind if s_tunnel is 0 */
	error = -EINVAL;
	if (sp->pppol2tp.s_tunnel == 0)
		goto end;

	/* Special case: prepare tunnel socket if s_session and
	 * d_session is 0. Otherwise look up tunnel using supplied
	 * tunnel id.
	 */
	if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
		tunnel_sock = pppol2tp_prepare_tunnel_socket(sp->pppol2tp.fd,
							     sp->pppol2tp.s_tunnel,
							     &error);
		if (tunnel_sock == NULL)
			goto end;

		tunnel = tunnel_sock->sk_user_data;
	} else {
		tunnel = pppol2tp_tunnel_find(sp->pppol2tp.s_tunnel);

		/* Error if we can't find the tunnel */
		error = -ENOENT;
		if (tunnel == NULL)
			goto end;

		tunnel_sock = tunnel->sock;
	}

	/* Check that this session doesn't already exist */
	error = -EEXIST;
	session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
	if (session != NULL)
		goto end;

	/* Allocate and initialize a new session context. */
	session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
	if (session == NULL) {
		error = -ENOMEM;
		goto end;
	}

	skb_queue_head_init(&session->reorder_q);

	session->magic	     = L2TP_SESSION_MAGIC;
	session->owner	     = current->pid;
	session->sock	     = sk;
	session->tunnel	     = tunnel;
	session->tunnel_sock = tunnel_sock;
	session->tunnel_addr = sp->pppol2tp;
	sprintf(&session->name[0], "sess %hu/%hu",
		session->tunnel_addr.s_tunnel,
		session->tunnel_addr.s_session);

	session->stats.tunnel_id  = session->tunnel_addr.s_tunnel;
	session->stats.session_id = session->tunnel_addr.s_session;

	INIT_HLIST_NODE(&session->hlist);

	/* Inherit debug options from tunnel */
	session->debug = tunnel->debug;

	/* Default MTU must allow space for UDP/L2TP/PPP
	 * headers.
	 */
	session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;

	/* If PMTU discovery was enabled, use the MTU that was discovered */
	dst = sk_dst_get(sk);
	if (dst != NULL) {
		u32 pmtu = dst_mtu(__sk_dst_get(sk));
		if (pmtu != 0)
			session->mtu = session->mru = pmtu -
				PPPOL2TP_HEADER_OVERHEAD;
		dst_release(dst);
	}

	/* Special case: if source & dest session_id == 0x0000, this socket is
	 * being created to manage the tunnel. Don't add the session to the
	 * session hash list, just set up the internal context for use by
	 * ioctl() and sockopt() handlers.
	 */
	if ((session->tunnel_addr.s_session == 0) &&
	    (session->tunnel_addr.d_session == 0)) {
		error = 0;
		sk->sk_user_data = session;
		goto out_no_ppp;
	}

	/* Get tunnel context from the tunnel socket */
	tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
	if (tunnel == NULL) {
		error = -EBADF;
		goto end;
	}

	/* Right now, because we don't have a way to push the incoming skb's
	 * straight through the UDP layer, the only header we need to worry
	 * about is the L2TP header. This size is different depending on
	 * whether sequence numbers are enabled for the data channel.
	 */
	po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;

	po->chan.private = sk;
	po->chan.ops	 = &pppol2tp_chan_ops;
	po->chan.mtu	 = session->mtu;

	error = ppp_register_channel(&po->chan);
	if (error)
		goto end_put_tun;

	/* This is how we get the session context from the socket. */
	sk->sk_user_data = session;

	/* Add session to the tunnel's hash list */
	write_lock_bh(&tunnel->hlist_lock);
	hlist_add_head(&session->hlist,
		       pppol2tp_session_id_hash(tunnel,
						session->tunnel_addr.s_session));
	write_unlock_bh(&tunnel->hlist_lock);

	atomic_inc(&pppol2tp_session_count);

out_no_ppp:
	pppol2tp_tunnel_inc_refcount(tunnel);
	sk->sk_state = PPPOX_CONNECTED;
	PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
	       "%s: created\n", session->name);

end_put_tun:
	sock_put(tunnel_sock);
end:
	release_sock(sk);

	if (error != 0) {
		if (session)
			PRINTK(session->debug,
				PPPOL2TP_MSG_CONTROL, KERN_WARNING,
				"%s: connect failed: %d\n",
				session->name, error);
		else
			PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
				"connect failed: %d\n", error);
	}

	return error;
}

/* getname() support.
 */
static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
			    int *usockaddr_len, int peer)
{
	int len = sizeof(struct sockaddr_pppol2tp);
	struct sockaddr_pppol2tp sp;
	int error = 0;
	struct pppol2tp_session *session;

	error = -ENOTCONN;
	if (sock->sk->sk_state != PPPOX_CONNECTED)
		goto end;

	session = pppol2tp_sock_to_session(sock->sk);
	if (session == NULL) {
		error = -EBADF;
		goto end;
	}

	sp.sa_family	= AF_PPPOX;
	sp.sa_protocol	= PX_PROTO_OL2TP;
	memcpy(&sp.pppol2tp, &session->tunnel_addr,
	       sizeof(struct pppol2tp_addr));

	memcpy(uaddr, &sp, len);

	*usockaddr_len = len;

	error = 0;
	sock_put(sock->sk);

end:
	return error;
}

/****************************************************************************
 * ioctl() handlers.
 *
 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
 * sockets. However, in order to control kernel tunnel features, we allow
 * userspace to create a special "tunnel" PPPoX socket which is used for
 * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
 * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
 * calls.
 ****************************************************************************/

/* Session ioctl helper.
 */
static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
				  unsigned int cmd, unsigned long arg)
{
	struct ifreq ifr;
	int err = 0;
	struct sock *sk = session->sock;
	int val = (int) arg;

	PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
	       "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
	       session->name, cmd, arg);

	sock_hold(sk);

	switch (cmd) {
	case SIOCGIFMTU:
		err = -ENXIO;
		if (!(sk->sk_state & PPPOX_CONNECTED))
			break;

		err = -EFAULT;
		if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
			break;
		ifr.ifr_mtu = session->mtu;
		if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
			break;

		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get mtu=%d\n", session->name, session->mtu);
		err = 0;
		break;

	case SIOCSIFMTU:
		err = -ENXIO;
		if (!(sk->sk_state & PPPOX_CONNECTED))
			break;

		err = -EFAULT;
		if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
			break;

		session->mtu = ifr.ifr_mtu;

		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set mtu=%d\n", session->name, session->mtu);
		err = 0;
		break;

	case PPPIOCGMRU:
		err = -ENXIO;
		if (!(sk->sk_state & PPPOX_CONNECTED))
			break;

		err = -EFAULT;
		if (put_user(session->mru, (int __user *) arg))
			break;

		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get mru=%d\n", session->name, session->mru);
		err = 0;
		break;

	case PPPIOCSMRU:
		err = -ENXIO;
		if (!(sk->sk_state & PPPOX_CONNECTED))
			break;

		err = -EFAULT;
		if (get_user(val,(int __user *) arg))
			break;

		session->mru = val;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set mru=%d\n", session->name, session->mru);
		err = 0;
		break;

	case PPPIOCGFLAGS:
		err = -EFAULT;
		if (put_user(session->flags, (int __user *) arg))
			break;

		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get flags=%d\n", session->name, session->flags);
		err = 0;
		break;

	case PPPIOCSFLAGS:
		err = -EFAULT;
		if (get_user(val, (int __user *) arg))
			break;
		session->flags = val;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set flags=%d\n", session->name, session->flags);
		err = 0;
		break;

	case PPPIOCGL2TPSTATS:
		err = -ENXIO;
		if (!(sk->sk_state & PPPOX_CONNECTED))
			break;

		if (copy_to_user((void __user *) arg, &session->stats,
				 sizeof(session->stats)))
			break;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get L2TP stats\n", session->name);
		err = 0;
		break;

	default:
		err = -ENOSYS;
		break;
	}

	sock_put(sk);

	return err;
}

/* Tunnel ioctl helper.
 *
 * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
 * specifies a session_id, the session ioctl handler is called. This allows an
 * application to retrieve session stats via a tunnel socket.
 */
static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
				 unsigned int cmd, unsigned long arg)
{
	int err = 0;
	struct sock *sk = tunnel->sock;
	struct pppol2tp_ioc_stats stats_req;

	PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
	       "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
	       cmd, arg);

	sock_hold(sk);

	switch (cmd) {
	case PPPIOCGL2TPSTATS:
		err = -ENXIO;
		if (!(sk->sk_state & PPPOX_CONNECTED))
			break;

		if (copy_from_user(&stats_req, (void __user *) arg,
				   sizeof(stats_req))) {
			err = -EFAULT;
			break;
		}
		if (stats_req.session_id != 0) {
			/* resend to session ioctl handler */
			struct pppol2tp_session *session =
				pppol2tp_session_find(tunnel, stats_req.session_id);
			if (session != NULL)
				err = pppol2tp_session_ioctl(session, cmd, arg);
			else
				err = -EBADR;
			break;
		}
#ifdef CONFIG_XFRM
		tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
#endif
		if (copy_to_user((void __user *) arg, &tunnel->stats,
				 sizeof(tunnel->stats))) {
			err = -EFAULT;
			break;
		}
		PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get L2TP stats\n", tunnel->name);
		err = 0;
		break;

	default:
		err = -ENOSYS;
		break;
	}

	sock_put(sk);

	return err;
}

/* Main ioctl() handler.
 * Dispatch to tunnel or session helpers depending on the socket.
 */
static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
			  unsigned long arg)
{
	struct sock *sk = sock->sk;
	struct pppol2tp_session *session;
	struct pppol2tp_tunnel *tunnel;
	int err;

	if (!sk)
		return 0;

	err = -EBADF;
	if (sock_flag(sk, SOCK_DEAD) != 0)
		goto end;

	err = -ENOTCONN;
	if ((sk->sk_user_data == NULL) ||
	    (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
		goto end;

	/* Get session context from the socket */
	err = -EBADF;
	session = pppol2tp_sock_to_session(sk);
	if (session == NULL)
		goto end;

	/* Special case: if session's session_id is zero, treat ioctl as a
	 * tunnel ioctl
	 */
	if ((session->tunnel_addr.s_session == 0) &&
	    (session->tunnel_addr.d_session == 0)) {
		err = -EBADF;
		tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
		if (tunnel == NULL)
			goto end_put_sess;

		err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
		sock_put(session->tunnel_sock);
		goto end_put_sess;
	}

	err = pppol2tp_session_ioctl(session, cmd, arg);

end_put_sess:
	sock_put(sk);
end:
	return err;
}

/*****************************************************************************
 * setsockopt() / getsockopt() support.
 *
 * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
 * sockets. In order to control kernel tunnel features, we allow userspace to
 * create a special "tunnel" PPPoX socket which is used for control only.
 * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
 * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
 *****************************************************************************/

/* Tunnel setsockopt() helper.
 */
static int pppol2tp_tunnel_setsockopt(struct sock *sk,
				      struct pppol2tp_tunnel *tunnel,
				      int optname, int val)
{
	int err = 0;

	switch (optname) {
	case PPPOL2TP_SO_DEBUG:
		tunnel->debug = val;
		PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set debug=%x\n", tunnel->name, tunnel->debug);
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	return err;
}

/* Session setsockopt helper.
 */
static int pppol2tp_session_setsockopt(struct sock *sk,
				       struct pppol2tp_session *session,
				       int optname, int val)
{
	int err = 0;

	switch (optname) {
	case PPPOL2TP_SO_RECVSEQ:
		if ((val != 0) && (val != 1)) {
			err = -EINVAL;
			break;
		}
		session->recv_seq = val ? -1 : 0;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set recv_seq=%d\n", session->name,
		       session->recv_seq);
		break;

	case PPPOL2TP_SO_SENDSEQ:
		if ((val != 0) && (val != 1)) {
			err = -EINVAL;
			break;
		}
		session->send_seq = val ? -1 : 0;
		{
			struct sock *ssk      = session->sock;
			struct pppox_sock *po = pppox_sk(ssk);
			po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
				PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
		}
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set send_seq=%d\n", session->name, session->send_seq);
		break;

	case PPPOL2TP_SO_LNSMODE:
		if ((val != 0) && (val != 1)) {
			err = -EINVAL;
			break;
		}
		session->lns_mode = val ? -1 : 0;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set lns_mode=%d\n", session->name,
		       session->lns_mode);
		break;

	case PPPOL2TP_SO_DEBUG:
		session->debug = val;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set debug=%x\n", session->name, session->debug);
		break;

	case PPPOL2TP_SO_REORDERTO:
		session->reorder_timeout = msecs_to_jiffies(val);
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: set reorder_timeout=%d\n", session->name,
		       session->reorder_timeout);
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	return err;
}

/* Main setsockopt() entry point.
 * Does API checks, then calls either the tunnel or session setsockopt
 * handler, according to whether the PPPoL2TP socket is a for a regular
 * session or the special tunnel type.
 */
static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
			       char __user *optval, int optlen)
{
	struct sock *sk = sock->sk;
	struct pppol2tp_session *session = sk->sk_user_data;
	struct pppol2tp_tunnel *tunnel;
	int val;
	int err;

	if (level != SOL_PPPOL2TP)
		return udp_prot.setsockopt(sk, level, optname, optval, optlen);

	if (optlen < sizeof(int))
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

	err = -ENOTCONN;
	if (sk->sk_user_data == NULL)
		goto end;

	/* Get session context from the socket */
	err = -EBADF;
	session = pppol2tp_sock_to_session(sk);
	if (session == NULL)
		goto end;

	/* Special case: if session_id == 0x0000, treat as operation on tunnel
	 */
	if ((session->tunnel_addr.s_session == 0) &&
	    (session->tunnel_addr.d_session == 0)) {
		err = -EBADF;
		tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
		if (tunnel == NULL)
			goto end_put_sess;

		err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
		sock_put(session->tunnel_sock);
	} else
		err = pppol2tp_session_setsockopt(sk, session, optname, val);

	err = 0;

end_put_sess:
	sock_put(sk);
end:
	return err;
}

/* Tunnel getsockopt helper. Called with sock locked.
 */
static int pppol2tp_tunnel_getsockopt(struct sock *sk,
				      struct pppol2tp_tunnel *tunnel,
				      int optname, int *val)
{
	int err = 0;

	switch (optname) {
	case PPPOL2TP_SO_DEBUG:
		*val = tunnel->debug;
		PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get debug=%x\n", tunnel->name, tunnel->debug);
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	return err;
}

/* Session getsockopt helper. Called with sock locked.
 */
static int pppol2tp_session_getsockopt(struct sock *sk,
				       struct pppol2tp_session *session,
				       int optname, int *val)
{
	int err = 0;

	switch (optname) {
	case PPPOL2TP_SO_RECVSEQ:
		*val = session->recv_seq;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get recv_seq=%d\n", session->name, *val);
		break;

	case PPPOL2TP_SO_SENDSEQ:
		*val = session->send_seq;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get send_seq=%d\n", session->name, *val);
		break;

	case PPPOL2TP_SO_LNSMODE:
		*val = session->lns_mode;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get lns_mode=%d\n", session->name, *val);
		break;

	case PPPOL2TP_SO_DEBUG:
		*val = session->debug;
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get debug=%d\n", session->name, *val);
		break;

	case PPPOL2TP_SO_REORDERTO:
		*val = (int) jiffies_to_msecs(session->reorder_timeout);
		PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
		       "%s: get reorder_timeout=%d\n", session->name, *val);
		break;

	default:
		err = -ENOPROTOOPT;
	}

	return err;
}

/* Main getsockopt() entry point.
 * Does API checks, then calls either the tunnel or session getsockopt
 * handler, according to whether the PPPoX socket is a for a regular session
 * or the special tunnel type.
 */
static int pppol2tp_getsockopt(struct socket *sock, int level,
			       int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct pppol2tp_session *session = sk->sk_user_data;
	struct pppol2tp_tunnel *tunnel;
	int val, len;
	int err;

	if (level != SOL_PPPOL2TP)
		return udp_prot.getsockopt(sk, level, optname, optval, optlen);

	if (get_user(len, (int __user *) optlen))
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));

	if (len < 0)
		return -EINVAL;

	err = -ENOTCONN;
	if (sk->sk_user_data == NULL)
		goto end;

	/* Get the session context */
	err = -EBADF;
	session = pppol2tp_sock_to_session(sk);
	if (session == NULL)
		goto end;

	/* Special case: if session_id == 0x0000, treat as operation on tunnel */
	if ((session->tunnel_addr.s_session == 0) &&
	    (session->tunnel_addr.d_session == 0)) {
		err = -EBADF;
		tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
		if (tunnel == NULL)
			goto end_put_sess;

		err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
		sock_put(session->tunnel_sock);
	} else
		err = pppol2tp_session_getsockopt(sk, session, optname, &val);

	err = -EFAULT;
	if (put_user(len, (int __user *) optlen))
		goto end_put_sess;

	if (copy_to_user((void __user *) optval, &val, len))
		goto end_put_sess;

	err = 0;

end_put_sess:
	sock_put(sk);
end:
	return err;
}

/*****************************************************************************
 * /proc filesystem for debug
 *****************************************************************************/

#ifdef CONFIG_PROC_FS

#include <linux/seq_file.h>

struct pppol2tp_seq_data {
	struct pppol2tp_tunnel *tunnel; /* current tunnel */
	struct pppol2tp_session *session; /* NULL means get first session in tunnel */
};

static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
{
	struct pppol2tp_session *session = NULL;
	struct hlist_node *walk;
	int found = 0;
	int next = 0;
	int i;

	read_lock_bh(&tunnel->hlist_lock);
	for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
		hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
			if (curr == NULL) {
				found = 1;
				goto out;
			}
			if (session == curr) {
				next = 1;
				continue;
			}
			if (next) {
				found = 1;
				goto out;
			}
		}
	}
out:
	read_unlock_bh(&tunnel->hlist_lock);
	if (!found)
		session = NULL;

	return session;
}

static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_tunnel *curr)
{
	struct pppol2tp_tunnel *tunnel = NULL;

	read_lock_bh(&pppol2tp_tunnel_list_lock);
	if (list_is_last(&curr->list, &pppol2tp_tunnel_list)) {
		goto out;
	}
	tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
out:
	read_unlock_bh(&pppol2tp_tunnel_list_lock);

	return tunnel;
}

static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
{
	struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
	loff_t pos = *offs;

	if (!pos)
		goto out;

	BUG_ON(m->private == NULL);
	pd = m->private;

	if (pd->tunnel == NULL) {
		if (!list_empty(&pppol2tp_tunnel_list))
			pd->tunnel = list_entry(pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
	} else {
		pd->session = next_session(pd->tunnel, pd->session);
		if (pd->session == NULL) {
			pd->tunnel = next_tunnel(pd->tunnel);
		}
	}

	/* NULL tunnel and session indicates end of list */
	if ((pd->tunnel == NULL) && (pd->session == NULL))
		pd = NULL;

out:
	return pd;
}

static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
	(*pos)++;
	return NULL;
}

static void pppol2tp_seq_stop(struct seq_file *p, void *v)
{
	/* nothing to do */
}

static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
{
	struct pppol2tp_tunnel *tunnel = v;

	seq_printf(m, "\nTUNNEL '%s', %c %d\n",
		   tunnel->name,
		   (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
		   atomic_read(&tunnel->ref_count) - 1);
	seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
		   tunnel->debug,
		   (unsigned long long)tunnel->stats.tx_packets,
		   (unsigned long long)tunnel->stats.tx_bytes,
		   (unsigned long long)tunnel->stats.tx_errors,
		   (unsigned long long)tunnel->stats.rx_packets,
		   (unsigned long long)tunnel->stats.rx_bytes,
		   (unsigned long long)tunnel->stats.rx_errors);
}

static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
{
	struct pppol2tp_session *session = v;

	seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
		   "%04X/%04X %d %c\n",
		   session->name,
		   ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
		   ntohs(session->tunnel_addr.addr.sin_port),
		   session->tunnel_addr.s_tunnel,
		   session->tunnel_addr.s_session,
		   session->tunnel_addr.d_tunnel,
		   session->tunnel_addr.d_session,
		   session->sock->sk_state,
		   (session == session->sock->sk_user_data) ?
		   'Y' : 'N');
	seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
		   session->mtu, session->mru,
		   session->recv_seq ? 'R' : '-',
		   session->send_seq ? 'S' : '-',
		   session->lns_mode ? "LNS" : "LAC",
		   session->debug,
		   jiffies_to_msecs(session->reorder_timeout));
	seq_printf(m, "   %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
		   session->nr, session->ns,
		   (unsigned long long)session->stats.tx_packets,
		   (unsigned long long)session->stats.tx_bytes,
		   (unsigned long long)session->stats.tx_errors,
		   (unsigned long long)session->stats.rx_packets,
		   (unsigned long long)session->stats.rx_bytes,
		   (unsigned long long)session->stats.rx_errors);
}

static int pppol2tp_seq_show(struct seq_file *m, void *v)
{
	struct pppol2tp_seq_data *pd = v;

	/* display header on line 1 */
	if (v == SEQ_START_TOKEN) {
		seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
		seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
		seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
		seq_puts(m, "  SESSION name, addr/port src-tid/sid "
			 "dest-tid/sid state user-data-ok\n");
		seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
		seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
		goto out;
	}

	/* Show the tunnel or session context.
	 */
	if (pd->session == NULL)
		pppol2tp_seq_tunnel_show(m, pd->tunnel);
	else
		pppol2tp_seq_session_show(m, pd->session);

out:
	return 0;
}

static struct seq_operations pppol2tp_seq_ops = {
	.start		= pppol2tp_seq_start,
	.next		= pppol2tp_seq_next,
	.stop		= pppol2tp_seq_stop,
	.show		= pppol2tp_seq_show,
};

/* Called when our /proc file is opened. We allocate data for use when
 * iterating our tunnel / session contexts and store it in the private
 * data of the seq_file.
 */
static int pppol2tp_proc_open(struct inode *inode, struct file *file)
{
	struct seq_file *m;
	struct pppol2tp_seq_data *pd;
	int ret = 0;

	ret = seq_open(file, &pppol2tp_seq_ops);
	if (ret < 0)
		goto out;

	m = file->private_data;

	/* Allocate and fill our proc_data for access later */
	ret = -ENOMEM;
	m->private = kzalloc(sizeof(struct pppol2tp_seq_data), GFP_KERNEL);
	if (m->private == NULL)
		goto out;

	pd = m->private;
	ret = 0;

out:
	return ret;
}

/* Called when /proc file access completes.
 */
static int pppol2tp_proc_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = (struct seq_file *)file->private_data;

	kfree(m->private);
	m->private = NULL;

	return seq_release(inode, file);
}

static struct file_operations pppol2tp_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= pppol2tp_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= pppol2tp_proc_release,
};

static struct proc_dir_entry *pppol2tp_proc;

#endif /* CONFIG_PROC_FS */

/*****************************************************************************
 * Init and cleanup
 *****************************************************************************/

static struct proto_ops pppol2tp_ops = {
	.family		= AF_PPPOX,
	.owner		= THIS_MODULE,
	.release	= pppol2tp_release,
	.bind		= sock_no_bind,
	.connect	= pppol2tp_connect,
	.socketpair	= sock_no_socketpair,
	.accept		= sock_no_accept,
	.getname	= pppol2tp_getname,
	.poll		= datagram_poll,
	.listen		= sock_no_listen,
	.shutdown	= sock_no_shutdown,
	.setsockopt	= pppol2tp_setsockopt,
	.getsockopt	= pppol2tp_getsockopt,
	.sendmsg	= pppol2tp_sendmsg,
	.recvmsg	= pppol2tp_recvmsg,
	.mmap		= sock_no_mmap,
	.ioctl		= pppox_ioctl,
};

static struct pppox_proto pppol2tp_proto = {
	.create		= pppol2tp_create,
	.ioctl		= pppol2tp_ioctl
};

static int __init pppol2tp_init(void)
{
	int err;

	err = proto_register(&pppol2tp_sk_proto, 0);
	if (err)
		goto out;
	err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
	if (err)
		goto out_unregister_pppol2tp_proto;

#ifdef CONFIG_PROC_FS
	pppol2tp_proc = proc_net_fops_create(&init_net, "pppol2tp", 0,
					     &pppol2tp_proc_fops);
	if (!pppol2tp_proc) {
		err = -ENOMEM;
		goto out_unregister_pppox_proto;
	}
#endif /* CONFIG_PROC_FS */
	printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
	       PPPOL2TP_DRV_VERSION);

out:
	return err;
#ifdef CONFIG_PROC_FS
out_unregister_pppox_proto:
	unregister_pppox_proto(PX_PROTO_OL2TP);
#endif
out_unregister_pppol2tp_proto:
	proto_unregister(&pppol2tp_sk_proto);
	goto out;
}

static void __exit pppol2tp_exit(void)
{
	unregister_pppox_proto(PX_PROTO_OL2TP);

#ifdef CONFIG_PROC_FS
	remove_proc_entry("pppol2tp", init_net.proc_net);
#endif
	proto_unregister(&pppol2tp_sk_proto);
}

module_init(pppol2tp_init);
module_exit(pppol2tp_exit);

MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
	      "James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("PPP over L2TP over UDP");
MODULE_LICENSE("GPL");
MODULE_VERSION(PPPOL2TP_DRV_VERSION);