aboutsummaryrefslogtreecommitdiff
path: root/net/appletalk/ddp.c
blob: bfcf6be1d665c89e3f88c4f9e34c452a03ced57d (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
/*
 *	DDP:	An implementation of the AppleTalk DDP protocol for
 *		Ethernet 'ELAP'.
 *
 *		Alan Cox  <alan@lxorguk.ukuu.org.uk>
 *
 *		With more than a little assistance from
 *
 *		Wesley Craig <netatalk@umich.edu>
 *
 *	Fixes:
 *		Neil Horman		:	Added missing device ioctls
 *		Michael Callahan	:	Made routing work
 *		Wesley Craig		:	Fix probing to listen to a
 *						passed node id.
 *		Alan Cox		:	Added send/recvmsg support
 *		Alan Cox		:	Moved at. to protinfo in
 *						socket.
 *		Alan Cox		:	Added firewall hooks.
 *		Alan Cox		:	Supports new ARPHRD_LOOPBACK
 *		Christer Weinigel	: 	Routing and /proc fixes.
 *		Bradford Johnson	:	LocalTalk.
 *		Tom Dyas		:	Module support.
 *		Alan Cox		:	Hooks for PPP (based on the
 *						LocalTalk hook).
 *		Alan Cox		:	Posix bits
 *		Alan Cox/Mike Freeman	:	Possible fix to NBP problems
 *		Bradford Johnson	:	IP-over-DDP (experimental)
 *		Jay Schulist		:	Moved IP-over-DDP to its own
 *						driver file. (ipddp.c & ipddp.h)
 *		Jay Schulist		:	Made work as module with
 *						AppleTalk drivers, cleaned it.
 *		Rob Newberry		:	Added proxy AARP and AARP
 *						procfs, moved probing to AARP
 *						module.
 *              Adrian Sun/
 *              Michael Zuelsdorff      :       fix for net.0 packets. don't
 *                                              allow illegal ether/tokentalk
 *                                              port assignment. we lose a
 *                                              valid localtalk port as a
 *                                              result.
 *		Arnaldo C. de Melo	:	Cleanup, in preparation for
 *						shared skb support 8)
 *		Arnaldo C. de Melo	:	Move proc stuff to atalk_proc.c,
 *						use seq_file
 *
 *		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.
 *
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/termios.h>	/* For TIOCOUTQ/INQ */
#include <linux/compat.h>
#include <linux/slab.h>
#include <net/datalink.h>
#include <net/psnap.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/route.h>
#include <linux/atalk.h>
#include <linux/highmem.h>

struct datalink_proto *ddp_dl, *aarp_dl;
static const struct proto_ops atalk_dgram_ops;

/**************************************************************************\
*                                                                          *
* Handlers for the socket list.                                            *
*                                                                          *
\**************************************************************************/

HLIST_HEAD(atalk_sockets);
DEFINE_RWLOCK(atalk_sockets_lock);

static inline void __atalk_insert_socket(struct sock *sk)
{
	sk_add_node(sk, &atalk_sockets);
}

static inline void atalk_remove_socket(struct sock *sk)
{
	write_lock_bh(&atalk_sockets_lock);
	sk_del_node_init(sk);
	write_unlock_bh(&atalk_sockets_lock);
}

static struct sock *atalk_search_socket(struct sockaddr_at *to,
					struct atalk_iface *atif)
{
	struct sock *s;

	read_lock_bh(&atalk_sockets_lock);
	sk_for_each(s, &atalk_sockets) {
		struct atalk_sock *at = at_sk(s);

		if (to->sat_port != at->src_port)
			continue;

		if (to->sat_addr.s_net == ATADDR_ANYNET &&
		    to->sat_addr.s_node == ATADDR_BCAST)
			goto found;

		if (to->sat_addr.s_net == at->src_net &&
		    (to->sat_addr.s_node == at->src_node ||
		     to->sat_addr.s_node == ATADDR_BCAST ||
		     to->sat_addr.s_node == ATADDR_ANYNODE))
			goto found;

		/* XXXX.0 -- we got a request for this router. make sure
		 * that the node is appropriately set. */
		if (to->sat_addr.s_node == ATADDR_ANYNODE &&
		    to->sat_addr.s_net != ATADDR_ANYNET &&
		    atif->address.s_node == at->src_node) {
			to->sat_addr.s_node = atif->address.s_node;
			goto found;
		}
	}
	s = NULL;
found:
	read_unlock_bh(&atalk_sockets_lock);
	return s;
}

/**
 * atalk_find_or_insert_socket - Try to find a socket matching ADDR
 * @sk: socket to insert in the list if it is not there already
 * @sat: address to search for
 *
 * Try to find a socket matching ADDR in the socket list, if found then return
 * it. If not, insert SK into the socket list.
 *
 * This entire operation must execute atomically.
 */
static struct sock *atalk_find_or_insert_socket(struct sock *sk,
						struct sockaddr_at *sat)
{
	struct sock *s;
	struct atalk_sock *at;

	write_lock_bh(&atalk_sockets_lock);
	sk_for_each(s, &atalk_sockets) {
		at = at_sk(s);

		if (at->src_net == sat->sat_addr.s_net &&
		    at->src_node == sat->sat_addr.s_node &&
		    at->src_port == sat->sat_port)
			goto found;
	}
	s = NULL;
	__atalk_insert_socket(sk); /* Wheee, it's free, assign and insert. */
found:
	write_unlock_bh(&atalk_sockets_lock);
	return s;
}

static void atalk_destroy_timer(unsigned long data)
{
	struct sock *sk = (struct sock *)data;

	if (sk_has_allocations(sk)) {
		sk->sk_timer.expires = jiffies + SOCK_DESTROY_TIME;
		add_timer(&sk->sk_timer);
	} else
		sock_put(sk);
}

static inline void atalk_destroy_socket(struct sock *sk)
{
	atalk_remove_socket(sk);
	skb_queue_purge(&sk->sk_receive_queue);

	if (sk_has_allocations(sk)) {
		setup_timer(&sk->sk_timer, atalk_destroy_timer,
				(unsigned long)sk);
		sk->sk_timer.expires	= jiffies + SOCK_DESTROY_TIME;
		add_timer(&sk->sk_timer);
	} else
		sock_put(sk);
}

/**************************************************************************\
*                                                                          *
* Routing tables for the AppleTalk socket layer.                           *
*                                                                          *
\**************************************************************************/

/* Anti-deadlock ordering is atalk_routes_lock --> iface_lock -DaveM */
struct atalk_route *atalk_routes;
DEFINE_RWLOCK(atalk_routes_lock);

struct atalk_iface *atalk_interfaces;
DEFINE_RWLOCK(atalk_interfaces_lock);

/* For probing devices or in a routerless network */
struct atalk_route atrtr_default;

/* AppleTalk interface control */
/*
 * Drop a device. Doesn't drop any of its routes - that is the caller's
 * problem. Called when we down the interface or delete the address.
 */
static void atif_drop_device(struct net_device *dev)
{
	struct atalk_iface **iface = &atalk_interfaces;
	struct atalk_iface *tmp;

	write_lock_bh(&atalk_interfaces_lock);
	while ((tmp = *iface) != NULL) {
		if (tmp->dev == dev) {
			*iface = tmp->next;
			dev_put(dev);
			kfree(tmp);
			dev->atalk_ptr = NULL;
		} else
			iface = &tmp->next;
	}
	write_unlock_bh(&atalk_interfaces_lock);
}

static struct atalk_iface *atif_add_device(struct net_device *dev,
					   struct atalk_addr *sa)
{
	struct atalk_iface *iface = kzalloc(sizeof(*iface), GFP_KERNEL);

	if (!iface)
		goto out;

	dev_hold(dev);
	iface->dev = dev;
	dev->atalk_ptr = iface;
	iface->address = *sa;
	iface->status = 0;

	write_lock_bh(&atalk_interfaces_lock);
	iface->next = atalk_interfaces;
	atalk_interfaces = iface;
	write_unlock_bh(&atalk_interfaces_lock);
out:
	return iface;
}

/* Perform phase 2 AARP probing on our tentative address */
static int atif_probe_device(struct atalk_iface *atif)
{
	int netrange = ntohs(atif->nets.nr_lastnet) -
			ntohs(atif->nets.nr_firstnet) + 1;
	int probe_net = ntohs(atif->address.s_net);
	int probe_node = atif->address.s_node;
	int netct, nodect;

	/* Offset the network we start probing with */
	if (probe_net == ATADDR_ANYNET) {
		probe_net = ntohs(atif->nets.nr_firstnet);
		if (netrange)
			probe_net += jiffies % netrange;
	}
	if (probe_node == ATADDR_ANYNODE)
		probe_node = jiffies & 0xFF;

	/* Scan the networks */
	atif->status |= ATIF_PROBE;
	for (netct = 0; netct <= netrange; netct++) {
		/* Sweep the available nodes from a given start */
		atif->address.s_net = htons(probe_net);
		for (nodect = 0; nodect < 256; nodect++) {
			atif->address.s_node = (nodect + probe_node) & 0xFF;
			if (atif->address.s_node > 0 &&
			    atif->address.s_node < 254) {
				/* Probe a proposed address */
				aarp_probe_network(atif);

				if (!(atif->status & ATIF_PROBE_FAIL)) {
					atif->status &= ~ATIF_PROBE;
					return 0;
				}
			}
			atif->status &= ~ATIF_PROBE_FAIL;
		}
		probe_net++;
		if (probe_net > ntohs(atif->nets.nr_lastnet))
			probe_net = ntohs(atif->nets.nr_firstnet);
	}
	atif->status &= ~ATIF_PROBE;

	return -EADDRINUSE;	/* Network is full... */
}


/* Perform AARP probing for a proxy address */
static int atif_proxy_probe_device(struct atalk_iface *atif,
				   struct atalk_addr *proxy_addr)
{
	int netrange = ntohs(atif->nets.nr_lastnet) -
			ntohs(atif->nets.nr_firstnet) + 1;
	/* we probe the interface's network */
	int probe_net = ntohs(atif->address.s_net);
	int probe_node = ATADDR_ANYNODE;	    /* we'll take anything */
	int netct, nodect;

	/* Offset the network we start probing with */
	if (probe_net == ATADDR_ANYNET) {
		probe_net = ntohs(atif->nets.nr_firstnet);
		if (netrange)
			probe_net += jiffies % netrange;
	}

	if (probe_node == ATADDR_ANYNODE)
		probe_node = jiffies & 0xFF;

	/* Scan the networks */
	for (netct = 0; netct <= netrange; netct++) {
		/* Sweep the available nodes from a given start */
		proxy_addr->s_net = htons(probe_net);
		for (nodect = 0; nodect < 256; nodect++) {
			proxy_addr->s_node = (nodect + probe_node) & 0xFF;
			if (proxy_addr->s_node > 0 &&
			    proxy_addr->s_node < 254) {
				/* Tell AARP to probe a proposed address */
				int ret = aarp_proxy_probe_network(atif,
								    proxy_addr);

				if (ret != -EADDRINUSE)
					return ret;
			}
		}
		probe_net++;
		if (probe_net > ntohs(atif->nets.nr_lastnet))
			probe_net = ntohs(atif->nets.nr_firstnet);
	}

	return -EADDRINUSE;	/* Network is full... */
}


struct atalk_addr *atalk_find_dev_addr(struct net_device *dev)
{
	struct atalk_iface *iface = dev->atalk_ptr;
	return iface ? &iface->address : NULL;
}

static struct atalk_addr *atalk_find_primary(void)
{
	struct atalk_iface *fiface = NULL;
	struct atalk_addr *retval;
	struct atalk_iface *iface;

	/*
	 * Return a point-to-point interface only if
	 * there is no non-ptp interface available.
	 */
	read_lock_bh(&atalk_interfaces_lock);
	for (iface = atalk_interfaces; iface; iface = iface->next) {
		if (!fiface && !(iface->dev->flags & IFF_LOOPBACK))
			fiface = iface;
		if (!(iface->dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
			retval = &iface->address;
			goto out;
		}
	}

	if (fiface)
		retval = &fiface->address;
	else if (atalk_interfaces)
		retval = &atalk_interfaces->address;
	else
		retval = NULL;
out:
	read_unlock_bh(&atalk_interfaces_lock);
	return retval;
}

/*
 * Find a match for 'any network' - ie any of our interfaces with that
 * node number will do just nicely.
 */
static struct atalk_iface *atalk_find_anynet(int node, struct net_device *dev)
{
	struct atalk_iface *iface = dev->atalk_ptr;

	if (!iface || iface->status & ATIF_PROBE)
		goto out_err;

	if (node != ATADDR_BCAST &&
	    iface->address.s_node != node &&
	    node != ATADDR_ANYNODE)
		goto out_err;
out:
	return iface;
out_err:
	iface = NULL;
	goto out;
}

/* Find a match for a specific network:node pair */
static struct atalk_iface *atalk_find_interface(__be16 net, int node)
{
	struct atalk_iface *iface;

	read_lock_bh(&atalk_interfaces_lock);
	for (iface = atalk_interfaces; iface; iface = iface->next) {
		if ((node == ATADDR_BCAST ||
		     node == ATADDR_ANYNODE ||
		     iface->address.s_node == node) &&
		    iface->address.s_net == net &&
		    !(iface->status & ATIF_PROBE))
			break;

		/* XXXX.0 -- net.0 returns the iface associated with net */
		if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
		    ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
		    ntohs(net) <= ntohs(iface->nets.nr_lastnet))
			break;
	}
	read_unlock_bh(&atalk_interfaces_lock);
	return iface;
}


/*
 * Find a route for an AppleTalk packet. This ought to get cached in
 * the socket (later on...). We know about host routes and the fact
 * that a route must be direct to broadcast.
 */
static struct atalk_route *atrtr_find(struct atalk_addr *target)
{
	/*
	 * we must search through all routes unless we find a
	 * host route, because some host routes might overlap
	 * network routes
	 */
	struct atalk_route *net_route = NULL;
	struct atalk_route *r;

	read_lock_bh(&atalk_routes_lock);
	for (r = atalk_routes; r; r = r->next) {
		if (!(r->flags & RTF_UP))
			continue;

		if (r->target.s_net == target->s_net) {
			if (r->flags & RTF_HOST) {
				/*
				 * if this host route is for the target,
				 * the we're done
				 */
				if (r->target.s_node == target->s_node)
					goto out;
			} else
				/*
				 * this route will work if there isn't a
				 * direct host route, so cache it
				 */
				net_route = r;
		}
	}

	/*
	 * if we found a network route but not a direct host
	 * route, then return it
	 */
	if (net_route)
		r = net_route;
	else if (atrtr_default.dev)
		r = &atrtr_default;
	else /* No route can be found */
		r = NULL;
out:
	read_unlock_bh(&atalk_routes_lock);
	return r;
}


/*
 * Given an AppleTalk network, find the device to use. This can be
 * a simple lookup.
 */
struct net_device *atrtr_get_dev(struct atalk_addr *sa)
{
	struct atalk_route *atr = atrtr_find(sa);
	return atr ? atr->dev : NULL;
}

/* Set up a default router */
static void atrtr_set_default(struct net_device *dev)
{
	atrtr_default.dev	     = dev;
	atrtr_default.flags	     = RTF_UP;
	atrtr_default.gateway.s_net  = htons(0);
	atrtr_default.gateway.s_node = 0;
}

/*
 * Add a router. Basically make sure it looks valid and stuff the
 * entry in the list. While it uses netranges we always set them to one
 * entry to work like netatalk.
 */
static int atrtr_create(struct rtentry *r, struct net_device *devhint)
{
	struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
	struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
	struct atalk_route *rt;
	struct atalk_iface *iface, *riface;
	int retval = -EINVAL;

	/*
	 * Fixme: Raise/Lower a routing change semaphore for these
	 * operations.
	 */

	/* Validate the request */
	if (ta->sat_family != AF_APPLETALK ||
	    (!devhint && ga->sat_family != AF_APPLETALK))
		goto out;

	/* Now walk the routing table and make our decisions */
	write_lock_bh(&atalk_routes_lock);
	for (rt = atalk_routes; rt; rt = rt->next) {
		if (r->rt_flags != rt->flags)
			continue;

		if (ta->sat_addr.s_net == rt->target.s_net) {
			if (!(rt->flags & RTF_HOST))
				break;
			if (ta->sat_addr.s_node == rt->target.s_node)
				break;
		}
	}

	if (!devhint) {
		riface = NULL;

		read_lock_bh(&atalk_interfaces_lock);
		for (iface = atalk_interfaces; iface; iface = iface->next) {
			if (!riface &&
			    ntohs(ga->sat_addr.s_net) >=
					ntohs(iface->nets.nr_firstnet) &&
			    ntohs(ga->sat_addr.s_net) <=
					ntohs(iface->nets.nr_lastnet))
				riface = iface;

			if (ga->sat_addr.s_net == iface->address.s_net &&
			    ga->sat_addr.s_node == iface->address.s_node)
				riface = iface;
		}
		read_unlock_bh(&atalk_interfaces_lock);

		retval = -ENETUNREACH;
		if (!riface)
			goto out_unlock;

		devhint = riface->dev;
	}

	if (!rt) {
		rt = kzalloc(sizeof(*rt), GFP_ATOMIC);

		retval = -ENOBUFS;
		if (!rt)
			goto out_unlock;

		rt->next = atalk_routes;
		atalk_routes = rt;
	}

	/* Fill in the routing entry */
	rt->target  = ta->sat_addr;
	dev_hold(devhint);
	rt->dev     = devhint;
	rt->flags   = r->rt_flags;
	rt->gateway = ga->sat_addr;

	retval = 0;
out_unlock:
	write_unlock_bh(&atalk_routes_lock);
out:
	return retval;
}

/* Delete a route. Find it and discard it */
static int atrtr_delete(struct atalk_addr *addr)
{
	struct atalk_route **r = &atalk_routes;
	int retval = 0;
	struct atalk_route *tmp;

	write_lock_bh(&atalk_routes_lock);
	while ((tmp = *r) != NULL) {
		if (tmp->target.s_net == addr->s_net &&
		    (!(tmp->flags&RTF_GATEWAY) ||
		     tmp->target.s_node == addr->s_node)) {
			*r = tmp->next;
			dev_put(tmp->dev);
			kfree(tmp);
			goto out;
		}
		r = &tmp->next;
	}
	retval = -ENOENT;
out:
	write_unlock_bh(&atalk_routes_lock);
	return retval;
}

/*
 * Called when a device is downed. Just throw away any routes
 * via it.
 */
static void atrtr_device_down(struct net_device *dev)
{
	struct atalk_route **r = &atalk_routes;
	struct atalk_route *tmp;

	write_lock_bh(&atalk_routes_lock);
	while ((tmp = *r) != NULL) {
		if (tmp->dev == dev) {
			*r = tmp->next;
			dev_put(dev);
			kfree(tmp);
		} else
			r = &tmp->next;
	}
	write_unlock_bh(&atalk_routes_lock);

	if (atrtr_default.dev == dev)
		atrtr_set_default(NULL);
}

/* Actually down the interface */
static inline void atalk_dev_down(struct net_device *dev)
{
	atrtr_device_down(dev);	/* Remove all routes for the device */
	aarp_device_down(dev);	/* Remove AARP entries for the device */
	atif_drop_device(dev);	/* Remove the device */
}

/*
 * A device event has occurred. Watch for devices going down and
 * delete our use of them (iface and route).
 */
static int ddp_device_event(struct notifier_block *this, unsigned long event,
			    void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

	if (!net_eq(dev_net(dev), &init_net))
		return NOTIFY_DONE;

	if (event == NETDEV_DOWN)
		/* Discard any use of this */
		atalk_dev_down(dev);

	return NOTIFY_DONE;
}

/* ioctl calls. Shouldn't even need touching */
/* Device configuration ioctl calls */
static int atif_ioctl(int cmd, void __user *arg)
{
	static char aarp_mcast[6] = { 0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF };
	struct ifreq atreq;
	struct atalk_netrange *nr;
	struct sockaddr_at *sa;
	struct net_device *dev;
	struct atalk_iface *atif;
	int ct;
	int limit;
	struct rtentry rtdef;
	int add_route;

	if (copy_from_user(&atreq, arg, sizeof(atreq)))
		return -EFAULT;

	dev = __dev_get_by_name(&init_net, atreq.ifr_name);
	if (!dev)
		return -ENODEV;

	sa = (struct sockaddr_at *)&atreq.ifr_addr;
	atif = atalk_find_dev(dev);

	switch (cmd) {
	case SIOCSIFADDR:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (sa->sat_family != AF_APPLETALK)
			return -EINVAL;
		if (dev->type != ARPHRD_ETHER &&
		    dev->type != ARPHRD_LOOPBACK &&
		    dev->type != ARPHRD_LOCALTLK &&
		    dev->type != ARPHRD_PPP)
			return -EPROTONOSUPPORT;

		nr = (struct atalk_netrange *)&sa->sat_zero[0];
		add_route = 1;

		/*
		 * if this is a point-to-point iface, and we already
		 * have an iface for this AppleTalk address, then we
		 * should not add a route
		 */
		if ((dev->flags & IFF_POINTOPOINT) &&
		    atalk_find_interface(sa->sat_addr.s_net,
					 sa->sat_addr.s_node)) {
			printk(KERN_DEBUG "AppleTalk: point-to-point "
			       "interface added with "
			       "existing address\n");
			add_route = 0;
		}

		/*
		 * Phase 1 is fine on LocalTalk but we don't do
		 * EtherTalk phase 1. Anyone wanting to add it go ahead.
		 */
		if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
			return -EPROTONOSUPPORT;
		if (sa->sat_addr.s_node == ATADDR_BCAST ||
		    sa->sat_addr.s_node == 254)
			return -EINVAL;
		if (atif) {
			/* Already setting address */
			if (atif->status & ATIF_PROBE)
				return -EBUSY;

			atif->address.s_net  = sa->sat_addr.s_net;
			atif->address.s_node = sa->sat_addr.s_node;
			atrtr_device_down(dev);	/* Flush old routes */
		} else {
			atif = atif_add_device(dev, &sa->sat_addr);
			if (!atif)
				return -ENOMEM;
		}
		atif->nets = *nr;

		/*
		 * Check if the chosen address is used. If so we
		 * error and atalkd will try another.
		 */

		if (!(dev->flags & IFF_LOOPBACK) &&
		    !(dev->flags & IFF_POINTOPOINT) &&
		    atif_probe_device(atif) < 0) {
			atif_drop_device(dev);
			return -EADDRINUSE;
		}

		/* Hey it worked - add the direct routes */
		sa = (struct sockaddr_at *)&rtdef.rt_gateway;
		sa->sat_family = AF_APPLETALK;
		sa->sat_addr.s_net  = atif->address.s_net;
		sa->sat_addr.s_node = atif->address.s_node;
		sa = (struct sockaddr_at *)&rtdef.rt_dst;
		rtdef.rt_flags = RTF_UP;
		sa->sat_family = AF_APPLETALK;
		sa->sat_addr.s_node = ATADDR_ANYNODE;
		if (dev->flags & IFF_LOOPBACK ||
		    dev->flags & IFF_POINTOPOINT)
			rtdef.rt_flags |= RTF_HOST;

		/* Routerless initial state */
		if (nr->nr_firstnet == htons(0) &&
		    nr->nr_lastnet == htons(0xFFFE)) {
			sa->sat_addr.s_net = atif->address.s_net;
			atrtr_create(&rtdef, dev);
			atrtr_set_default(dev);
		} else {
			limit = ntohs(nr->nr_lastnet);
			if (limit - ntohs(nr->nr_firstnet) > 4096) {
				printk(KERN_WARNING "Too many routes/"
				       "iface.\n");
				return -EINVAL;
			}
			if (add_route)
				for (ct = ntohs(nr->nr_firstnet);
				     ct <= limit; ct++) {
					sa->sat_addr.s_net = htons(ct);
					atrtr_create(&rtdef, dev);
				}
		}
		dev_mc_add_global(dev, aarp_mcast);
		return 0;

	case SIOCGIFADDR:
		if (!atif)
			return -EADDRNOTAVAIL;

		sa->sat_family = AF_APPLETALK;
		sa->sat_addr = atif->address;
		break;

	case SIOCGIFBRDADDR:
		if (!atif)
			return -EADDRNOTAVAIL;

		sa->sat_family = AF_APPLETALK;
		sa->sat_addr.s_net = atif->address.s_net;
		sa->sat_addr.s_node = ATADDR_BCAST;
		break;

	case SIOCATALKDIFADDR:
	case SIOCDIFADDR:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (sa->sat_family != AF_APPLETALK)
			return -EINVAL;
		atalk_dev_down(dev);
		break;

	case SIOCSARP:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (sa->sat_family != AF_APPLETALK)
			return -EINVAL;
		/*
		 * for now, we only support proxy AARP on ELAP;
		 * we should be able to do it for LocalTalk, too.
		 */
		if (dev->type != ARPHRD_ETHER)
			return -EPROTONOSUPPORT;

		/*
		 * atif points to the current interface on this network;
		 * we aren't concerned about its current status (at
		 * least for now), but it has all the settings about
		 * the network we're going to probe. Consequently, it
		 * must exist.
		 */
		if (!atif)
			return -EADDRNOTAVAIL;

		nr = (struct atalk_netrange *)&(atif->nets);
		/*
		 * Phase 1 is fine on Localtalk but we don't do
		 * Ethertalk phase 1. Anyone wanting to add it go ahead.
		 */
		if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
			return -EPROTONOSUPPORT;

		if (sa->sat_addr.s_node == ATADDR_BCAST ||
		    sa->sat_addr.s_node == 254)
			return -EINVAL;

		/*
		 * Check if the chosen address is used. If so we
		 * error and ATCP will try another.
		 */
		if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
			return -EADDRINUSE;

		/*
		 * We now have an address on the local network, and
		 * the AARP code will defend it for us until we take it
		 * down. We don't set up any routes right now, because
		 * ATCP will install them manually via SIOCADDRT.
		 */
		break;

	case SIOCDARP:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (sa->sat_family != AF_APPLETALK)
			return -EINVAL;
		if (!atif)
			return -EADDRNOTAVAIL;

		/* give to aarp module to remove proxy entry */
		aarp_proxy_remove(atif->dev, &(sa->sat_addr));
		return 0;
	}

	return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
}

/* Routing ioctl() calls */
static int atrtr_ioctl(unsigned int cmd, void __user *arg)
{
	struct rtentry rt;

	if (copy_from_user(&rt, arg, sizeof(rt)))
		return -EFAULT;

	switch (cmd) {
	case SIOCDELRT:
		if (rt.rt_dst.sa_family != AF_APPLETALK)
			return -EINVAL;
		return atrtr_delete(&((struct sockaddr_at *)
				      &rt.rt_dst)->sat_addr);

	case SIOCADDRT: {
		struct net_device *dev = NULL;
		if (rt.rt_dev) {
			char name[IFNAMSIZ];
			if (copy_from_user(name, rt.rt_dev, IFNAMSIZ-1))
				return -EFAULT;
			name[IFNAMSIZ-1] = '\0';
			dev = __dev_get_by_name(&init_net, name);
			if (!dev)
				return -ENODEV;
		}
		return atrtr_create(&rt, dev);
	}
	}
	return -EINVAL;
}

/**************************************************************************\
*                                                                          *
* Handling for system calls applied via the various interfaces to an       *
* AppleTalk socket object.                                                 *
*                                                                          *
\**************************************************************************/

/*
 * Checksum: This is 'optional'. It's quite likely also a good
 * candidate for assembler hackery 8)
 */
static unsigned long atalk_sum_partial(const unsigned char *data,
				       int len, unsigned long sum)
{
	/* This ought to be unwrapped neatly. I'll trust gcc for now */
	while (len--) {
		sum += *data++;
		sum = rol16(sum, 1);
	}
	return sum;
}

/*  Checksum skb data --  similar to skb_checksum  */
static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
				   int len, unsigned long sum)
{
	int start = skb_headlen(skb);
	struct sk_buff *frag_iter;
	int i, copy;

	/* checksum stuff in header space */
	if ((copy = start - offset) > 0) {
		if (copy > len)
			copy = len;
		sum = atalk_sum_partial(skb->data + offset, copy, sum);
		if ((len -= copy) == 0)
			return sum;

		offset += copy;
	}

	/* checksum stuff in frags */
	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		int end;
		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
		WARN_ON(start > offset + len);

		end = start + skb_frag_size(frag);
		if ((copy = end - offset) > 0) {
			u8 *vaddr;

			if (copy > len)
				copy = len;
			vaddr = kmap_atomic(skb_frag_page(frag));
			sum = atalk_sum_partial(vaddr + frag->page_offset +
						  offset - start, copy, sum);
			kunmap_atomic(vaddr);

			if (!(len -= copy))
				return sum;
			offset += copy;
		}
		start = end;
	}

	skb_walk_frags(skb, frag_iter) {
		int end;

		WARN_ON(start > offset + len);

		end = start + frag_iter->len;
		if ((copy = end - offset) > 0) {
			if (copy > len)
				copy = len;
			sum = atalk_sum_skb(frag_iter, offset - start,
					    copy, sum);
			if ((len -= copy) == 0)
				return sum;
			offset += copy;
		}
		start = end;
	}

	BUG_ON(len > 0);

	return sum;
}

static __be16 atalk_checksum(const struct sk_buff *skb, int len)
{
	unsigned long sum;

	/* skip header 4 bytes */
	sum = atalk_sum_skb(skb, 4, len-4, 0);

	/* Use 0xFFFF for 0. 0 itself means none */
	return sum ? htons((unsigned short)sum) : htons(0xFFFF);
}

static struct proto ddp_proto = {
	.name	  = "DDP",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct atalk_sock),
};

/*
 * Create a socket. Initialise the socket, blank the addresses
 * set the state.
 */
static int atalk_create(struct net *net, struct socket *sock, int protocol,
			int kern)
{
	struct sock *sk;
	int rc = -ESOCKTNOSUPPORT;

	if (!net_eq(net, &init_net))
		return -EAFNOSUPPORT;

	/*
	 * We permit SOCK_DGRAM and RAW is an extension. It is trivial to do
	 * and gives you the full ELAP frame. Should be handy for CAP 8)
	 */
	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
		goto out;
	rc = -ENOMEM;
	sk = sk_alloc(net, PF_APPLETALK, GFP_KERNEL, &ddp_proto);
	if (!sk)
		goto out;
	rc = 0;
	sock->ops = &atalk_dgram_ops;
	sock_init_data(sock, sk);

	/* Checksums on by default */
	sock_set_flag(sk, SOCK_ZAPPED);
out:
	return rc;
}

/* Free a socket. No work needed */
static int atalk_release(struct socket *sock)
{
	struct sock *sk = sock->sk;

	if (sk) {
		sock_hold(sk);
		lock_sock(sk);

		sock_orphan(sk);
		sock->sk = NULL;
		atalk_destroy_socket(sk);

		release_sock(sk);
		sock_put(sk);
	}
	return 0;
}

/**
 * atalk_pick_and_bind_port - Pick a source port when one is not given
 * @sk: socket to insert into the tables
 * @sat: address to search for
 *
 * Pick a source port when one is not given. If we can find a suitable free
 * one, we insert the socket into the tables using it.
 *
 * This whole operation must be atomic.
 */
static int atalk_pick_and_bind_port(struct sock *sk, struct sockaddr_at *sat)
{
	int retval;

	write_lock_bh(&atalk_sockets_lock);

	for (sat->sat_port = ATPORT_RESERVED;
	     sat->sat_port < ATPORT_LAST;
	     sat->sat_port++) {
		struct sock *s;

		sk_for_each(s, &atalk_sockets) {
			struct atalk_sock *at = at_sk(s);

			if (at->src_net == sat->sat_addr.s_net &&
			    at->src_node == sat->sat_addr.s_node &&
			    at->src_port == sat->sat_port)
				goto try_next_port;
		}

		/* Wheee, it's free, assign and insert. */
		__atalk_insert_socket(sk);
		at_sk(sk)->src_port = sat->sat_port;
		retval = 0;
		goto out;

try_next_port:;
	}

	retval = -EBUSY;
out:
	write_unlock_bh(&atalk_sockets_lock);
	return retval;
}

static int atalk_autobind(struct sock *sk)
{
	struct atalk_sock *at = at_sk(sk);
	struct sockaddr_at sat;
	struct atalk_addr *ap = atalk_find_primary();
	int n = -EADDRNOTAVAIL;

	if (!ap || ap->s_net == htons(ATADDR_ANYNET))
		goto out;

	at->src_net  = sat.sat_addr.s_net  = ap->s_net;
	at->src_node = sat.sat_addr.s_node = ap->s_node;

	n = atalk_pick_and_bind_port(sk, &sat);
	if (!n)
		sock_reset_flag(sk, SOCK_ZAPPED);
out:
	return n;
}

/* Set the address 'our end' of the connection */
static int atalk_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sockaddr_at *addr = (struct sockaddr_at *)uaddr;
	struct sock *sk = sock->sk;
	struct atalk_sock *at = at_sk(sk);
	int err;

	if (!sock_flag(sk, SOCK_ZAPPED) ||
	    addr_len != sizeof(struct sockaddr_at))
		return -EINVAL;

	if (addr->sat_family != AF_APPLETALK)
		return -EAFNOSUPPORT;

	lock_sock(sk);
	if (addr->sat_addr.s_net == htons(ATADDR_ANYNET)) {
		struct atalk_addr *ap = atalk_find_primary();

		err = -EADDRNOTAVAIL;
		if (!ap)
			goto out;

		at->src_net  = addr->sat_addr.s_net = ap->s_net;
		at->src_node = addr->sat_addr.s_node = ap->s_node;
	} else {
		err = -EADDRNOTAVAIL;
		if (!atalk_find_interface(addr->sat_addr.s_net,
					  addr->sat_addr.s_node))
			goto out;

		at->src_net  = addr->sat_addr.s_net;
		at->src_node = addr->sat_addr.s_node;
	}

	if (addr->sat_port == ATADDR_ANYPORT) {
		err = atalk_pick_and_bind_port(sk, addr);

		if (err < 0)
			goto out;
	} else {
		at->src_port = addr->sat_port;

		err = -EADDRINUSE;
		if (atalk_find_or_insert_socket(sk, addr))
			goto out;
	}

	sock_reset_flag(sk, SOCK_ZAPPED);
	err = 0;
out:
	release_sock(sk);
	return err;
}

/* Set the address we talk to */
static int atalk_connect(struct socket *sock, struct sockaddr *uaddr,
			 int addr_len, int flags)
{
	struct sock *sk = sock->sk;
	struct atalk_sock *at = at_sk(sk);
	struct sockaddr_at *addr;
	int err;

	sk->sk_state   = TCP_CLOSE;
	sock->state = SS_UNCONNECTED;

	if (addr_len != sizeof(*addr))
		return -EINVAL;

	addr = (struct sockaddr_at *)uaddr;

	if (addr->sat_family != AF_APPLETALK)
		return -EAFNOSUPPORT;

	if (addr->sat_addr.s_node == ATADDR_BCAST &&
	    !sock_flag(sk, SOCK_BROADCAST)) {
#if 1
		pr_warn("atalk_connect: %s is broken and did not set SO_BROADCAST.\n",
			current->comm);
#else
		return -EACCES;
#endif
	}

	lock_sock(sk);
	err = -EBUSY;
	if (sock_flag(sk, SOCK_ZAPPED))
		if (atalk_autobind(sk) < 0)
			goto out;

	err = -ENETUNREACH;
	if (!atrtr_get_dev(&addr->sat_addr))
		goto out;

	at->dest_port = addr->sat_port;
	at->dest_net  = addr->sat_addr.s_net;
	at->dest_node = addr->sat_addr.s_node;

	sock->state  = SS_CONNECTED;
	sk->sk_state = TCP_ESTABLISHED;
	err = 0;
out:
	release_sock(sk);
	return err;
}

/*
 * Find the name of an AppleTalk socket. Just copy the right
 * fields into the sockaddr.
 */
static int atalk_getname(struct socket *sock, struct sockaddr *uaddr,
			 int *uaddr_len, int peer)
{
	struct sockaddr_at sat;
	struct sock *sk = sock->sk;
	struct atalk_sock *at = at_sk(sk);
	int err;

	lock_sock(sk);
	err = -ENOBUFS;
	if (sock_flag(sk, SOCK_ZAPPED))
		if (atalk_autobind(sk) < 0)
			goto out;

	*uaddr_len = sizeof(struct sockaddr_at);
	memset(&sat, 0, sizeof(sat));

	if (peer) {
		err = -ENOTCONN;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;

		sat.sat_addr.s_net  = at->dest_net;
		sat.sat_addr.s_node = at->dest_node;
		sat.sat_port	    = at->dest_port;
	} else {
		sat.sat_addr.s_net  = at->src_net;
		sat.sat_addr.s_node = at->src_node;
		sat.sat_port	    = at->src_port;
	}

	err = 0;
	sat.sat_family = AF_APPLETALK;
	memcpy(uaddr, &sat, sizeof(sat));

out:
	release_sock(sk);
	return err;
}

#if defined(CONFIG_IPDDP) || defined(CONFIG_IPDDP_MODULE)
static __inline__ int is_ip_over_ddp(struct sk_buff *skb)
{
	return skb->data[12] == 22;
}

static int handle_ip_over_ddp(struct sk_buff *skb)
{
	struct net_device *dev = __dev_get_by_name(&init_net, "ipddp0");
	struct net_device_stats *stats;

	/* This needs to be able to handle ipddp"N" devices */
	if (!dev) {
		kfree_skb(skb);
		return NET_RX_DROP;
	}

	skb->protocol = htons(ETH_P_IP);
	skb_pull(skb, 13);
	skb->dev   = dev;
	skb_reset_transport_header(skb);

	stats = netdev_priv(dev);
	stats->rx_packets++;
	stats->rx_bytes += skb->len + 13;
	return netif_rx(skb);  /* Send the SKB up to a higher place. */
}
#else
/* make it easy for gcc to optimize this test out, i.e. kill the code */
#define is_ip_over_ddp(skb) 0
#define handle_ip_over_ddp(skb) 0
#endif

static int atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
			      struct ddpehdr *ddp, __u16 len_hops, int origlen)
{
	struct atalk_route *rt;
	struct atalk_addr ta;

	/*
	 * Don't route multicast, etc., packets, or packets sent to "this
	 * network"
	 */
	if (skb->pkt_type != PACKET_HOST || !ddp->deh_dnet) {
		/*
		 * FIXME:
		 *
		 * Can it ever happen that a packet is from a PPP iface and
		 * needs to be broadcast onto the default network?
		 */
		if (dev->type == ARPHRD_PPP)
			printk(KERN_DEBUG "AppleTalk: didn't forward broadcast "
					  "packet received from PPP iface\n");
		goto free_it;
	}

	ta.s_net  = ddp->deh_dnet;
	ta.s_node = ddp->deh_dnode;

	/* Route the packet */
	rt = atrtr_find(&ta);
	/* increment hops count */
	len_hops += 1 << 10;
	if (!rt || !(len_hops & (15 << 10)))
		goto free_it;

	/* FIXME: use skb->cb to be able to use shared skbs */

	/*
	 * Route goes through another gateway, so set the target to the
	 * gateway instead.
	 */

	if (rt->flags & RTF_GATEWAY) {
		ta.s_net  = rt->gateway.s_net;
		ta.s_node = rt->gateway.s_node;
	}

	/* Fix up skb->len field */
	skb_trim(skb, min_t(unsigned int, origlen,
			    (rt->dev->hard_header_len +
			     ddp_dl->header_length + (len_hops & 1023))));

	/* FIXME: use skb->cb to be able to use shared skbs */
	ddp->deh_len_hops = htons(len_hops);

	/*
	 * Send the buffer onwards
	 *
	 * Now we must always be careful. If it's come from LocalTalk to
	 * EtherTalk it might not fit
	 *
	 * Order matters here: If a packet has to be copied to make a new
	 * headroom (rare hopefully) then it won't need unsharing.
	 *
	 * Note. ddp-> becomes invalid at the realloc.
	 */
	if (skb_headroom(skb) < 22) {
		/* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
		struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
		kfree_skb(skb);
		skb = nskb;
	} else
		skb = skb_unshare(skb, GFP_ATOMIC);

	/*
	 * If the buffer didn't vanish into the lack of space bitbucket we can
	 * send it.
	 */
	if (skb == NULL)
		goto drop;

	if (aarp_send_ddp(rt->dev, skb, &ta, NULL) == NET_XMIT_DROP)
		return NET_RX_DROP;
	return NET_RX_SUCCESS;
free_it:
	kfree_skb(skb);
drop:
	return NET_RX_DROP;
}

/**
 *	atalk_rcv - Receive a packet (in skb) from device dev
 *	@skb - packet received
 *	@dev - network device where the packet comes from
 *	@pt - packet type
 *
 *	Receive a packet (in skb) from device dev. This has come from the SNAP
 *	decoder, and on entry skb->transport_header is the DDP header, skb->len
 *	is the DDP header, skb->len is the DDP length. The physical headers
 *	have been extracted. PPP should probably pass frames marked as for this
 *	layer.  [ie ARPHRD_ETHERTALK]
 */
static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
		     struct packet_type *pt, struct net_device *orig_dev)
{
	struct ddpehdr *ddp;
	struct sock *sock;
	struct atalk_iface *atif;
	struct sockaddr_at tosat;
	int origlen;
	__u16 len_hops;

	if (!net_eq(dev_net(dev), &init_net))
		goto drop;

	/* Don't mangle buffer if shared */
	if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
		goto out;

	/* Size check and make sure header is contiguous */
	if (!pskb_may_pull(skb, sizeof(*ddp)))
		goto drop;

	ddp = ddp_hdr(skb);

	len_hops = ntohs(ddp->deh_len_hops);

	/* Trim buffer in case of stray trailing data */
	origlen = skb->len;
	skb_trim(skb, min_t(unsigned int, skb->len, len_hops & 1023));

	/*
	 * Size check to see if ddp->deh_len was crap
	 * (Otherwise we'll detonate most spectacularly
	 * in the middle of atalk_checksum() or recvmsg()).
	 */
	if (skb->len < sizeof(*ddp) || skb->len < (len_hops & 1023)) {
		pr_debug("AppleTalk: dropping corrupted frame (deh_len=%u, "
			 "skb->len=%u)\n", len_hops & 1023, skb->len);
		goto drop;
	}

	/*
	 * Any checksums. Note we don't do htons() on this == is assumed to be
	 * valid for net byte orders all over the networking code...
	 */
	if (ddp->deh_sum &&
	    atalk_checksum(skb, len_hops & 1023) != ddp->deh_sum)
		/* Not a valid AppleTalk frame - dustbin time */
		goto drop;

	/* Check the packet is aimed at us */
	if (!ddp->deh_dnet)	/* Net 0 is 'this network' */
		atif = atalk_find_anynet(ddp->deh_dnode, dev);
	else
		atif = atalk_find_interface(ddp->deh_dnet, ddp->deh_dnode);

	if (!atif) {
		/* Not ours, so we route the packet via the correct
		 * AppleTalk iface
		 */
		return atalk_route_packet(skb, dev, ddp, len_hops, origlen);
	}

	/* if IP over DDP is not selected this code will be optimized out */
	if (is_ip_over_ddp(skb))
		return handle_ip_over_ddp(skb);
	/*
	 * Which socket - atalk_search_socket() looks for a *full match*
	 * of the <net, node, port> tuple.
	 */
	tosat.sat_addr.s_net  = ddp->deh_dnet;
	tosat.sat_addr.s_node = ddp->deh_dnode;
	tosat.sat_port	      = ddp->deh_dport;

	sock = atalk_search_socket(&tosat, atif);
	if (!sock) /* But not one of our sockets */
		goto drop;

	/* Queue packet (standard) */
	if (sock_queue_rcv_skb(sock, skb) < 0)
		goto drop;

	return NET_RX_SUCCESS;

drop:
	kfree_skb(skb);
out:
	return NET_RX_DROP;

}

/*
 * Receive a LocalTalk frame. We make some demands on the caller here.
 * Caller must provide enough headroom on the packet to pull the short
 * header and append a long one.
 */
static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
		     struct packet_type *pt, struct net_device *orig_dev)
{
	if (!net_eq(dev_net(dev), &init_net))
		goto freeit;

	/* Expand any short form frames */
	if (skb_mac_header(skb)[2] == 1) {
		struct ddpehdr *ddp;
		/* Find our address */
		struct atalk_addr *ap = atalk_find_dev_addr(dev);

		if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
			goto freeit;

		/* Don't mangle buffer if shared */
		if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
			return 0;

		/*
		 * The push leaves us with a ddephdr not an shdr, and
		 * handily the port bytes in the right place preset.
		 */
		ddp = (struct ddpehdr *) skb_push(skb, sizeof(*ddp) - 4);

		/* Now fill in the long header */

		/*
		 * These two first. The mac overlays the new source/dest
		 * network information so we MUST copy these before
		 * we write the network numbers !
		 */

		ddp->deh_dnode = skb_mac_header(skb)[0];     /* From physical header */
		ddp->deh_snode = skb_mac_header(skb)[1];     /* From physical header */

		ddp->deh_dnet  = ap->s_net;	/* Network number */
		ddp->deh_snet  = ap->s_net;
		ddp->deh_sum   = 0;		/* No checksum */
		/*
		 * Not sure about this bit...
		 */
		/* Non routable, so force a drop if we slip up later */
		ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
	}
	skb_reset_transport_header(skb);

	return atalk_rcv(skb, dev, pt, orig_dev);
freeit:
	kfree_skb(skb);
	return 0;
}

static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
			 size_t len)
{
	struct sock *sk = sock->sk;
	struct atalk_sock *at = at_sk(sk);
	DECLARE_SOCKADDR(struct sockaddr_at *, usat, msg->msg_name);
	int flags = msg->msg_flags;
	int loopback = 0;
	struct sockaddr_at local_satalk, gsat;
	struct sk_buff *skb;
	struct net_device *dev;
	struct ddpehdr *ddp;
	int size;
	struct atalk_route *rt;
	int err;

	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
		return -EINVAL;

	if (len > DDP_MAXSZ)
		return -EMSGSIZE;

	lock_sock(sk);
	if (usat) {
		err = -EBUSY;
		if (sock_flag(sk, SOCK_ZAPPED))
			if (atalk_autobind(sk) < 0)
				goto out;

		err = -EINVAL;
		if (msg->msg_namelen < sizeof(*usat) ||
		    usat->sat_family != AF_APPLETALK)
			goto out;

		err = -EPERM;
		/* netatalk didn't implement this check */
		if (usat->sat_addr.s_node == ATADDR_BCAST &&
		    !sock_flag(sk, SOCK_BROADCAST)) {
			goto out;
		}
	} else {
		err = -ENOTCONN;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;
		usat = &local_satalk;
		usat->sat_family      = AF_APPLETALK;
		usat->sat_port	      = at->dest_port;
		usat->sat_addr.s_node = at->dest_node;
		usat->sat_addr.s_net  = at->dest_net;
	}

	/* Build a packet */
	SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);

	/* For headers */
	size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;

	if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
		rt = atrtr_find(&usat->sat_addr);
	} else {
		struct atalk_addr at_hint;

		at_hint.s_node = 0;
		at_hint.s_net  = at->src_net;

		rt = atrtr_find(&at_hint);
	}
	err = ENETUNREACH;
	if (!rt)
		goto out;

	dev = rt->dev;

	SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
			sk, size, dev->name);

	size += dev->hard_header_len;
	release_sock(sk);
	skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
	lock_sock(sk);
	if (!skb)
		goto out;

	skb_reserve(skb, ddp_dl->header_length);
	skb_reserve(skb, dev->hard_header_len);
	skb->dev = dev;

	SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);

	ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
	ddp->deh_len_hops  = htons(len + sizeof(*ddp));
	ddp->deh_dnet  = usat->sat_addr.s_net;
	ddp->deh_snet  = at->src_net;
	ddp->deh_dnode = usat->sat_addr.s_node;
	ddp->deh_snode = at->src_node;
	ddp->deh_dport = usat->sat_port;
	ddp->deh_sport = at->src_port;

	SOCK_DEBUG(sk, "SK %p: Copy user data (%Zd bytes).\n", sk, len);

	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
	if (err) {
		kfree_skb(skb);
		err = -EFAULT;
		goto out;
	}

	if (sk->sk_no_check_tx)
		ddp->deh_sum = 0;
	else
		ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));

	/*
	 * Loopback broadcast packets to non gateway targets (ie routes
	 * to group we are in)
	 */
	if (ddp->deh_dnode == ATADDR_BCAST &&
	    !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
		struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);

		if (skb2) {
			loopback = 1;
			SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
			/*
			 * If it fails it is queued/sent above in the aarp queue
			 */
			aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL);
		}
	}

	if (dev->flags & IFF_LOOPBACK || loopback) {
		SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
		/* loop back */
		skb_orphan(skb);
		if (ddp->deh_dnode == ATADDR_BCAST) {
			struct atalk_addr at_lo;

			at_lo.s_node = 0;
			at_lo.s_net  = 0;

			rt = atrtr_find(&at_lo);
			if (!rt) {
				kfree_skb(skb);
				err = -ENETUNREACH;
				goto out;
			}
			dev = rt->dev;
			skb->dev = dev;
		}
		ddp_dl->request(ddp_dl, skb, dev->dev_addr);
	} else {
		SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
		if (rt->flags & RTF_GATEWAY) {
		    gsat.sat_addr = rt->gateway;
		    usat = &gsat;
		}

		/*
		 * If it fails it is queued/sent above in the aarp queue
		 */
		aarp_send_ddp(dev, skb, &usat->sat_addr, NULL);
	}
	SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);

out:
	release_sock(sk);
	return err ? : len;
}

static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
			 size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct ddpehdr *ddp;
	int copied = 0;
	int offset = 0;
	int err = 0;
	struct sk_buff *skb;

	skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
						flags & MSG_DONTWAIT, &err);
	lock_sock(sk);

	if (!skb)
		goto out;

	/* FIXME: use skb->cb to be able to use shared skbs */
	ddp = ddp_hdr(skb);
	copied = ntohs(ddp->deh_len_hops) & 1023;

	if (sk->sk_type != SOCK_RAW) {
		offset = sizeof(*ddp);
		copied -= offset;
	}

	if (copied > size) {
		copied = size;
		msg->msg_flags |= MSG_TRUNC;
	}
	err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, copied);

	if (!err && msg->msg_name) {
		DECLARE_SOCKADDR(struct sockaddr_at *, sat, msg->msg_name);
		sat->sat_family      = AF_APPLETALK;
		sat->sat_port        = ddp->deh_sport;
		sat->sat_addr.s_node = ddp->deh_snode;
		sat->sat_addr.s_net  = ddp->deh_snet;
		msg->msg_namelen     = sizeof(*sat);
	}

	skb_free_datagram(sk, skb);	/* Free the datagram. */

out:
	release_sock(sk);
	return err ? : copied;
}


/*
 * AppleTalk ioctl calls.
 */
static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	int rc = -ENOIOCTLCMD;
	struct sock *sk = sock->sk;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	/* Protocol layer */
	case TIOCOUTQ: {
		long amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);

		if (amount < 0)
			amount = 0;
		rc = put_user(amount, (int __user *)argp);
		break;
	}
	case TIOCINQ: {
		/*
		 * These two are safe on a single CPU system as only
		 * user tasks fiddle here
		 */
		struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
		long amount = 0;

		if (skb)
		amount = skb->len - sizeof(struct ddpehdr);
		rc = put_user(amount, (int __user *)argp);
		break;
	}
	case SIOCGSTAMP:
		rc = sock_get_timestamp(sk, argp);
		break;
	case SIOCGSTAMPNS:
		rc = sock_get_timestampns(sk, argp);
		break;
	/* Routing */
	case SIOCADDRT:
	case SIOCDELRT:
		rc = -EPERM;
		if (capable(CAP_NET_ADMIN))
			rc = atrtr_ioctl(cmd, argp);
		break;
	/* Interface */
	case SIOCGIFADDR:
	case SIOCSIFADDR:
	case SIOCGIFBRDADDR:
	case SIOCATALKDIFADDR:
	case SIOCDIFADDR:
	case SIOCSARP:		/* proxy AARP */
	case SIOCDARP:		/* proxy AARP */
		rtnl_lock();
		rc = atif_ioctl(cmd, argp);
		rtnl_unlock();
		break;
	}

	return rc;
}


#ifdef CONFIG_COMPAT
static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	/*
	 * SIOCATALKDIFADDR is a SIOCPROTOPRIVATE ioctl number, so we
	 * cannot handle it in common code. The data we access if ifreq
	 * here is compatible, so we can simply call the native
	 * handler.
	 */
	if (cmd == SIOCATALKDIFADDR)
		return atalk_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));

	return -ENOIOCTLCMD;
}
#endif


static const struct net_proto_family atalk_family_ops = {
	.family		= PF_APPLETALK,
	.create		= atalk_create,
	.owner		= THIS_MODULE,
};

static const struct proto_ops atalk_dgram_ops = {
	.family		= PF_APPLETALK,
	.owner		= THIS_MODULE,
	.release	= atalk_release,
	.bind		= atalk_bind,
	.connect	= atalk_connect,
	.socketpair	= sock_no_socketpair,
	.accept		= sock_no_accept,
	.getname	= atalk_getname,
	.poll		= datagram_poll,
	.ioctl		= atalk_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= atalk_compat_ioctl,
#endif
	.listen		= sock_no_listen,
	.shutdown	= sock_no_shutdown,
	.setsockopt	= sock_no_setsockopt,
	.getsockopt	= sock_no_getsockopt,
	.sendmsg	= atalk_sendmsg,
	.recvmsg	= atalk_recvmsg,
	.mmap		= sock_no_mmap,
	.sendpage	= sock_no_sendpage,
};

static struct notifier_block ddp_notifier = {
	.notifier_call	= ddp_device_event,
};

static struct packet_type ltalk_packet_type __read_mostly = {
	.type		= cpu_to_be16(ETH_P_LOCALTALK),
	.func		= ltalk_rcv,
};

static struct packet_type ppptalk_packet_type __read_mostly = {
	.type		= cpu_to_be16(ETH_P_PPPTALK),
	.func		= atalk_rcv,
};

static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };

/* Export symbols for use by drivers when AppleTalk is a module */
EXPORT_SYMBOL(atrtr_get_dev);
EXPORT_SYMBOL(atalk_find_dev_addr);

static const char atalk_err_snap[] __initconst =
	KERN_CRIT "Unable to register DDP with SNAP.\n";

/* Called by proto.c on kernel start up */
static int __init atalk_init(void)
{
	int rc = proto_register(&ddp_proto, 0);

	if (rc != 0)
		goto out;

	(void)sock_register(&atalk_family_ops);
	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
	if (!ddp_dl)
		printk(atalk_err_snap);

	dev_add_pack(&ltalk_packet_type);
	dev_add_pack(&ppptalk_packet_type);

	register_netdevice_notifier(&ddp_notifier);
	aarp_proto_init();
	atalk_proc_init();
	atalk_register_sysctl();
out:
	return rc;
}
module_init(atalk_init);

/*
 * No explicit module reference count manipulation is needed in the
 * protocol. Socket layer sets module reference count for us
 * and interfaces reference counting is done
 * by the network device layer.
 *
 * Ergo, before the AppleTalk module can be removed, all AppleTalk
 * sockets be closed from user space.
 */
static void __exit atalk_exit(void)
{
#ifdef CONFIG_SYSCTL
	atalk_unregister_sysctl();
#endif /* CONFIG_SYSCTL */
	atalk_proc_exit();
	aarp_cleanup_module();	/* General aarp clean-up. */
	unregister_netdevice_notifier(&ddp_notifier);
	dev_remove_pack(&ltalk_packet_type);
	dev_remove_pack(&ppptalk_packet_type);
	unregister_snap_client(ddp_dl);
	sock_unregister(PF_APPLETALK);
	proto_unregister(&ddp_proto);
}
module_exit(atalk_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
MODULE_DESCRIPTION("AppleTalk 0.20\n");
MODULE_ALIAS_NETPROTO(PF_APPLETALK);