aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/fib_trie.c
blob: 2a6fdc2708c6a25d974343bb3771bab893630a83 (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
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
/*
 *   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.
 *
 *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
 *     & Swedish University of Agricultural Sciences.
 *
 *   Jens Laas <jens.laas@data.slu.se> Swedish University of
 *     Agricultural Sciences.
 *
 *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
 *
 * This work is based on the LPC-trie which is originally described in:
 *
 * An experimental study of compression methods for dynamic tries
 * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
 * http://www.csc.kth.se/~snilsson/software/dyntrie2/
 *
 *
 * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
 * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
 *
 *
 * Code from fib_hash has been reused which includes the following header:
 *
 *
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		IPv4 FIB: lookup engine and maintenance routines.
 *
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *		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.
 *
 * Substantial contributions to this work comes from:
 *
 *		David S. Miller, <davem@davemloft.net>
 *		Stephen Hemminger <shemminger@osdl.org>
 *		Paul E. McKenney <paulmck@us.ibm.com>
 *		Patrick McHardy <kaber@trash.net>
 */

#define VERSION "0.409"

#include <asm/uaccess.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/prefetch.h>
#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include "fib_lookup.h"

#define MAX_STAT_DEPTH 32

#define KEYLENGTH (8*sizeof(t_key))

typedef unsigned int t_key;

#define T_TNODE 0
#define T_LEAF  1
#define NODE_TYPE_MASK	0x1UL
#define NODE_TYPE(node) ((node)->parent & NODE_TYPE_MASK)

#define IS_TNODE(n) (!(n->parent & T_LEAF))
#define IS_LEAF(n) (n->parent & T_LEAF)

struct rt_trie_node {
	unsigned long parent;
	t_key key;
};

struct leaf {
	unsigned long parent;
	t_key key;
	struct hlist_head list;
	struct rcu_head rcu;
};

struct leaf_info {
	struct hlist_node hlist;
	int plen;
	u32 mask_plen; /* ntohl(inet_make_mask(plen)) */
	struct list_head falh;
	struct rcu_head rcu;
};

struct tnode {
	unsigned long parent;
	t_key key;
	unsigned char pos;		/* 2log(KEYLENGTH) bits needed */
	unsigned char bits;		/* 2log(KEYLENGTH) bits needed */
	unsigned int full_children;	/* KEYLENGTH bits needed */
	unsigned int empty_children;	/* KEYLENGTH bits needed */
	union {
		struct rcu_head rcu;
		struct work_struct work;
		struct tnode *tnode_free;
	};
	struct rt_trie_node __rcu *child[0];
};

#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats {
	unsigned int gets;
	unsigned int backtrack;
	unsigned int semantic_match_passed;
	unsigned int semantic_match_miss;
	unsigned int null_node_hit;
	unsigned int resize_node_skipped;
};
#endif

struct trie_stat {
	unsigned int totdepth;
	unsigned int maxdepth;
	unsigned int tnodes;
	unsigned int leaves;
	unsigned int nullpointers;
	unsigned int prefixes;
	unsigned int nodesizes[MAX_STAT_DEPTH];
};

struct trie {
	struct rt_trie_node __rcu *trie;
#ifdef CONFIG_IP_FIB_TRIE_STATS
	struct trie_use_stats stats;
#endif
};

static void put_child(struct trie *t, struct tnode *tn, int i, struct rt_trie_node *n);
static void tnode_put_child_reorg(struct tnode *tn, int i, struct rt_trie_node *n,
				  int wasfull);
static struct rt_trie_node *resize(struct trie *t, struct tnode *tn);
static struct tnode *inflate(struct trie *t, struct tnode *tn);
static struct tnode *halve(struct trie *t, struct tnode *tn);
/* tnodes to free after resize(); protected by RTNL */
static struct tnode *tnode_free_head;
static size_t tnode_free_size;

/*
 * synchronize_rcu after call_rcu for that many pages; it should be especially
 * useful before resizing the root node with PREEMPT_NONE configs; the value was
 * obtained experimentally, aiming to avoid visible slowdown.
 */
static const int sync_pages = 128;

static struct kmem_cache *fn_alias_kmem __read_mostly;
static struct kmem_cache *trie_leaf_kmem __read_mostly;

/*
 * caller must hold RTNL
 */
static inline struct tnode *node_parent(const struct rt_trie_node *node)
{
	unsigned long parent;

	parent = rcu_dereference_index_check(node->parent, lockdep_rtnl_is_held());

	return (struct tnode *)(parent & ~NODE_TYPE_MASK);
}

/*
 * caller must hold RCU read lock or RTNL
 */
static inline struct tnode *node_parent_rcu(const struct rt_trie_node *node)
{
	unsigned long parent;

	parent = rcu_dereference_index_check(node->parent, rcu_read_lock_held() ||
							   lockdep_rtnl_is_held());

	return (struct tnode *)(parent & ~NODE_TYPE_MASK);
}

/* Same as rcu_assign_pointer
 * but that macro() assumes that value is a pointer.
 */
static inline void node_set_parent(struct rt_trie_node *node, struct tnode *ptr)
{
	smp_wmb();
	node->parent = (unsigned long)ptr | NODE_TYPE(node);
}

/*
 * caller must hold RTNL
 */
static inline struct rt_trie_node *tnode_get_child(const struct tnode *tn, unsigned int i)
{
	BUG_ON(i >= 1U << tn->bits);

	return rtnl_dereference(tn->child[i]);
}

/*
 * caller must hold RCU read lock or RTNL
 */
static inline struct rt_trie_node *tnode_get_child_rcu(const struct tnode *tn, unsigned int i)
{
	BUG_ON(i >= 1U << tn->bits);

	return rcu_dereference_rtnl(tn->child[i]);
}

static inline int tnode_child_length(const struct tnode *tn)
{
	return 1 << tn->bits;
}

static inline t_key mask_pfx(t_key k, unsigned int l)
{
	return (l == 0) ? 0 : k >> (KEYLENGTH-l) << (KEYLENGTH-l);
}

static inline t_key tkey_extract_bits(t_key a, unsigned int offset, unsigned int bits)
{
	if (offset < KEYLENGTH)
		return ((t_key)(a << offset)) >> (KEYLENGTH - bits);
	else
		return 0;
}

static inline int tkey_equals(t_key a, t_key b)
{
	return a == b;
}

static inline int tkey_sub_equals(t_key a, int offset, int bits, t_key b)
{
	if (bits == 0 || offset >= KEYLENGTH)
		return 1;
	bits = bits > KEYLENGTH ? KEYLENGTH : bits;
	return ((a ^ b) << offset) >> (KEYLENGTH - bits) == 0;
}

static inline int tkey_mismatch(t_key a, int offset, t_key b)
{
	t_key diff = a ^ b;
	int i = offset;

	if (!diff)
		return 0;
	while ((diff << i) >> (KEYLENGTH-1) == 0)
		i++;
	return i;
}

/*
  To understand this stuff, an understanding of keys and all their bits is
  necessary. Every node in the trie has a key associated with it, but not
  all of the bits in that key are significant.

  Consider a node 'n' and its parent 'tp'.

  If n is a leaf, every bit in its key is significant. Its presence is
  necessitated by path compression, since during a tree traversal (when
  searching for a leaf - unless we are doing an insertion) we will completely
  ignore all skipped bits we encounter. Thus we need to verify, at the end of
  a potentially successful search, that we have indeed been walking the
  correct key path.

  Note that we can never "miss" the correct key in the tree if present by
  following the wrong path. Path compression ensures that segments of the key
  that are the same for all keys with a given prefix are skipped, but the
  skipped part *is* identical for each node in the subtrie below the skipped
  bit! trie_insert() in this implementation takes care of that - note the
  call to tkey_sub_equals() in trie_insert().

  if n is an internal node - a 'tnode' here, the various parts of its key
  have many different meanings.

  Example:
  _________________________________________________________________
  | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
  -----------------------------------------------------------------
    0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15

  _________________________________________________________________
  | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
  -----------------------------------------------------------------
   16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31

  tp->pos = 7
  tp->bits = 3
  n->pos = 15
  n->bits = 4

  First, let's just ignore the bits that come before the parent tp, that is
  the bits from 0 to (tp->pos-1). They are *known* but at this point we do
  not use them for anything.

  The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
  index into the parent's child array. That is, they will be used to find
  'n' among tp's children.

  The bits from (tp->pos + tp->bits) to (n->pos - 1) - "S" - are skipped bits
  for the node n.

  All the bits we have seen so far are significant to the node n. The rest
  of the bits are really not needed or indeed known in n->key.

  The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
  n's child array, and will of course be different for each child.


  The rest of the bits, from (n->pos + n->bits) onward, are completely unknown
  at this point.

*/

static inline void check_tnode(const struct tnode *tn)
{
	WARN_ON(tn && tn->pos+tn->bits > 32);
}

static const int halve_threshold = 25;
static const int inflate_threshold = 50;
static const int halve_threshold_root = 15;
static const int inflate_threshold_root = 30;

static void __alias_free_mem(struct rcu_head *head)
{
	struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
	kmem_cache_free(fn_alias_kmem, fa);
}

static inline void alias_free_mem_rcu(struct fib_alias *fa)
{
	call_rcu(&fa->rcu, __alias_free_mem);
}

static void __leaf_free_rcu(struct rcu_head *head)
{
	struct leaf *l = container_of(head, struct leaf, rcu);
	kmem_cache_free(trie_leaf_kmem, l);
}

static inline void free_leaf(struct leaf *l)
{
	call_rcu_bh(&l->rcu, __leaf_free_rcu);
}

static inline void free_leaf_info(struct leaf_info *leaf)
{
	kfree_rcu(leaf, rcu);
}

static struct tnode *tnode_alloc(size_t size)
{
	if (size <= PAGE_SIZE)
		return kzalloc(size, GFP_KERNEL);
	else
		return vzalloc(size);
}

static void __tnode_vfree(struct work_struct *arg)
{
	struct tnode *tn = container_of(arg, struct tnode, work);
	vfree(tn);
}

static void __tnode_free_rcu(struct rcu_head *head)
{
	struct tnode *tn = container_of(head, struct tnode, rcu);
	size_t size = sizeof(struct tnode) +
		      (sizeof(struct rt_trie_node *) << tn->bits);

	if (size <= PAGE_SIZE)
		kfree(tn);
	else {
		INIT_WORK(&tn->work, __tnode_vfree);
		schedule_work(&tn->work);
	}
}

static inline void tnode_free(struct tnode *tn)
{
	if (IS_LEAF(tn))
		free_leaf((struct leaf *) tn);
	else
		call_rcu(&tn->rcu, __tnode_free_rcu);
}

static void tnode_free_safe(struct tnode *tn)
{
	BUG_ON(IS_LEAF(tn));
	tn->tnode_free = tnode_free_head;
	tnode_free_head = tn;
	tnode_free_size += sizeof(struct tnode) +
			   (sizeof(struct rt_trie_node *) << tn->bits);
}

static void tnode_free_flush(void)
{
	struct tnode *tn;

	while ((tn = tnode_free_head)) {
		tnode_free_head = tn->tnode_free;
		tn->tnode_free = NULL;
		tnode_free(tn);
	}

	if (tnode_free_size >= PAGE_SIZE * sync_pages) {
		tnode_free_size = 0;
		synchronize_rcu();
	}
}

static struct leaf *leaf_new(void)
{
	struct leaf *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
	if (l) {
		l->parent = T_LEAF;
		INIT_HLIST_HEAD(&l->list);
	}
	return l;
}

static struct leaf_info *leaf_info_new(int plen)
{
	struct leaf_info *li = kmalloc(sizeof(struct leaf_info),  GFP_KERNEL);
	if (li) {
		li->plen = plen;
		li->mask_plen = ntohl(inet_make_mask(plen));
		INIT_LIST_HEAD(&li->falh);
	}
	return li;
}

static struct tnode *tnode_new(t_key key, int pos, int bits)
{
	size_t sz = sizeof(struct tnode) + (sizeof(struct rt_trie_node *) << bits);
	struct tnode *tn = tnode_alloc(sz);

	if (tn) {
		tn->parent = T_TNODE;
		tn->pos = pos;
		tn->bits = bits;
		tn->key = key;
		tn->full_children = 0;
		tn->empty_children = 1<<bits;
	}

	pr_debug("AT %p s=%zu %zu\n", tn, sizeof(struct tnode),
		 sizeof(struct rt_trie_node *) << bits);
	return tn;
}

/*
 * Check whether a tnode 'n' is "full", i.e. it is an internal node
 * and no bits are skipped. See discussion in dyntree paper p. 6
 */

static inline int tnode_full(const struct tnode *tn, const struct rt_trie_node *n)
{
	if (n == NULL || IS_LEAF(n))
		return 0;

	return ((struct tnode *) n)->pos == tn->pos + tn->bits;
}

static inline void put_child(struct trie *t, struct tnode *tn, int i,
			     struct rt_trie_node *n)
{
	tnode_put_child_reorg(tn, i, n, -1);
}

 /*
  * Add a child at position i overwriting the old value.
  * Update the value of full_children and empty_children.
  */

static void tnode_put_child_reorg(struct tnode *tn, int i, struct rt_trie_node *n,
				  int wasfull)
{
	struct rt_trie_node *chi = rtnl_dereference(tn->child[i]);
	int isfull;

	BUG_ON(i >= 1<<tn->bits);

	/* update emptyChildren */
	if (n == NULL && chi != NULL)
		tn->empty_children++;
	else if (n != NULL && chi == NULL)
		tn->empty_children--;

	/* update fullChildren */
	if (wasfull == -1)
		wasfull = tnode_full(tn, chi);

	isfull = tnode_full(tn, n);
	if (wasfull && !isfull)
		tn->full_children--;
	else if (!wasfull && isfull)
		tn->full_children++;

	if (n)
		node_set_parent(n, tn);

	rcu_assign_pointer(tn->child[i], n);
}

#define MAX_WORK 10
static struct rt_trie_node *resize(struct trie *t, struct tnode *tn)
{
	int i;
	struct tnode *old_tn;
	int inflate_threshold_use;
	int halve_threshold_use;
	int max_work;

	if (!tn)
		return NULL;

	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
		 tn, inflate_threshold, halve_threshold);

	/* No children */
	if (tn->empty_children == tnode_child_length(tn)) {
		tnode_free_safe(tn);
		return NULL;
	}
	/* One child */
	if (tn->empty_children == tnode_child_length(tn) - 1)
		goto one_child;
	/*
	 * Double as long as the resulting node has a number of
	 * nonempty nodes that are above the threshold.
	 */

	/*
	 * From "Implementing a dynamic compressed trie" by Stefan Nilsson of
	 * the Helsinki University of Technology and Matti Tikkanen of Nokia
	 * Telecommunications, page 6:
	 * "A node is doubled if the ratio of non-empty children to all
	 * children in the *doubled* node is at least 'high'."
	 *
	 * 'high' in this instance is the variable 'inflate_threshold'. It
	 * is expressed as a percentage, so we multiply it with
	 * tnode_child_length() and instead of multiplying by 2 (since the
	 * child array will be doubled by inflate()) and multiplying
	 * the left-hand side by 100 (to handle the percentage thing) we
	 * multiply the left-hand side by 50.
	 *
	 * The left-hand side may look a bit weird: tnode_child_length(tn)
	 * - tn->empty_children is of course the number of non-null children
	 * in the current node. tn->full_children is the number of "full"
	 * children, that is non-null tnodes with a skip value of 0.
	 * All of those will be doubled in the resulting inflated tnode, so
	 * we just count them one extra time here.
	 *
	 * A clearer way to write this would be:
	 *
	 * to_be_doubled = tn->full_children;
	 * not_to_be_doubled = tnode_child_length(tn) - tn->empty_children -
	 *     tn->full_children;
	 *
	 * new_child_length = tnode_child_length(tn) * 2;
	 *
	 * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
	 *      new_child_length;
	 * if (new_fill_factor >= inflate_threshold)
	 *
	 * ...and so on, tho it would mess up the while () loop.
	 *
	 * anyway,
	 * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
	 *      inflate_threshold
	 *
	 * avoid a division:
	 * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
	 *      inflate_threshold * new_child_length
	 *
	 * expand not_to_be_doubled and to_be_doubled, and shorten:
	 * 100 * (tnode_child_length(tn) - tn->empty_children +
	 *    tn->full_children) >= inflate_threshold * new_child_length
	 *
	 * expand new_child_length:
	 * 100 * (tnode_child_length(tn) - tn->empty_children +
	 *    tn->full_children) >=
	 *      inflate_threshold * tnode_child_length(tn) * 2
	 *
	 * shorten again:
	 * 50 * (tn->full_children + tnode_child_length(tn) -
	 *    tn->empty_children) >= inflate_threshold *
	 *    tnode_child_length(tn)
	 *
	 */

	check_tnode(tn);

	/* Keep root node larger  */

	if (!node_parent((struct rt_trie_node *)tn)) {
		inflate_threshold_use = inflate_threshold_root;
		halve_threshold_use = halve_threshold_root;
	} else {
		inflate_threshold_use = inflate_threshold;
		halve_threshold_use = halve_threshold;
	}

	max_work = MAX_WORK;
	while ((tn->full_children > 0 &&  max_work-- &&
		50 * (tn->full_children + tnode_child_length(tn)
		      - tn->empty_children)
		>= inflate_threshold_use * tnode_child_length(tn))) {

		old_tn = tn;
		tn = inflate(t, tn);

		if (IS_ERR(tn)) {
			tn = old_tn;
#ifdef CONFIG_IP_FIB_TRIE_STATS
			t->stats.resize_node_skipped++;
#endif
			break;
		}
	}

	check_tnode(tn);

	/* Return if at least one inflate is run */
	if (max_work != MAX_WORK)
		return (struct rt_trie_node *) tn;

	/*
	 * Halve as long as the number of empty children in this
	 * node is above threshold.
	 */

	max_work = MAX_WORK;
	while (tn->bits > 1 &&  max_work-- &&
	       100 * (tnode_child_length(tn) - tn->empty_children) <
	       halve_threshold_use * tnode_child_length(tn)) {

		old_tn = tn;
		tn = halve(t, tn);
		if (IS_ERR(tn)) {
			tn = old_tn;
#ifdef CONFIG_IP_FIB_TRIE_STATS
			t->stats.resize_node_skipped++;
#endif
			break;
		}
	}


	/* Only one child remains */
	if (tn->empty_children == tnode_child_length(tn) - 1) {
one_child:
		for (i = 0; i < tnode_child_length(tn); i++) {
			struct rt_trie_node *n;

			n = rtnl_dereference(tn->child[i]);
			if (!n)
				continue;

			/* compress one level */

			node_set_parent(n, NULL);
			tnode_free_safe(tn);
			return n;
		}
	}
	return (struct rt_trie_node *) tn;
}


static void tnode_clean_free(struct tnode *tn)
{
	int i;
	struct tnode *tofree;

	for (i = 0; i < tnode_child_length(tn); i++) {
		tofree = (struct tnode *)rtnl_dereference(tn->child[i]);
		if (tofree)
			tnode_free(tofree);
	}
	tnode_free(tn);
}

static struct tnode *inflate(struct trie *t, struct tnode *tn)
{
	struct tnode *oldtnode = tn;
	int olen = tnode_child_length(tn);
	int i;

	pr_debug("In inflate\n");

	tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits + 1);

	if (!tn)
		return ERR_PTR(-ENOMEM);

	/*
	 * Preallocate and store tnodes before the actual work so we
	 * don't get into an inconsistent state if memory allocation
	 * fails. In case of failure we return the oldnode and  inflate
	 * of tnode is ignored.
	 */

	for (i = 0; i < olen; i++) {
		struct tnode *inode;

		inode = (struct tnode *) tnode_get_child(oldtnode, i);
		if (inode &&
		    IS_TNODE(inode) &&
		    inode->pos == oldtnode->pos + oldtnode->bits &&
		    inode->bits > 1) {
			struct tnode *left, *right;
			t_key m = ~0U << (KEYLENGTH - 1) >> inode->pos;

			left = tnode_new(inode->key&(~m), inode->pos + 1,
					 inode->bits - 1);
			if (!left)
				goto nomem;

			right = tnode_new(inode->key|m, inode->pos + 1,
					  inode->bits - 1);

			if (!right) {
				tnode_free(left);
				goto nomem;
			}

			put_child(t, tn, 2*i, (struct rt_trie_node *) left);
			put_child(t, tn, 2*i+1, (struct rt_trie_node *) right);
		}
	}

	for (i = 0; i < olen; i++) {
		struct tnode *inode;
		struct rt_trie_node *node = tnode_get_child(oldtnode, i);
		struct tnode *left, *right;
		int size, j;

		/* An empty child */
		if (node == NULL)
			continue;

		/* A leaf or an internal node with skipped bits */

		if (IS_LEAF(node) || ((struct tnode *) node)->pos >
		   tn->pos + tn->bits - 1) {
			if (tkey_extract_bits(node->key,
					      oldtnode->pos + oldtnode->bits,
					      1) == 0)
				put_child(t, tn, 2*i, node);
			else
				put_child(t, tn, 2*i+1, node);
			continue;
		}

		/* An internal node with two children */
		inode = (struct tnode *) node;

		if (inode->bits == 1) {
			put_child(t, tn, 2*i, rtnl_dereference(inode->child[0]));
			put_child(t, tn, 2*i+1, rtnl_dereference(inode->child[1]));

			tnode_free_safe(inode);
			continue;
		}

		/* An internal node with more than two children */

		/* We will replace this node 'inode' with two new
		 * ones, 'left' and 'right', each with half of the
		 * original children. The two new nodes will have
		 * a position one bit further down the key and this
		 * means that the "significant" part of their keys
		 * (see the discussion near the top of this file)
		 * will differ by one bit, which will be "0" in
		 * left's key and "1" in right's key. Since we are
		 * moving the key position by one step, the bit that
		 * we are moving away from - the bit at position
		 * (inode->pos) - is the one that will differ between
		 * left and right. So... we synthesize that bit in the
		 * two  new keys.
		 * The mask 'm' below will be a single "one" bit at
		 * the position (inode->pos)
		 */

		/* Use the old key, but set the new significant
		 *   bit to zero.
		 */

		left = (struct tnode *) tnode_get_child(tn, 2*i);
		put_child(t, tn, 2*i, NULL);

		BUG_ON(!left);

		right = (struct tnode *) tnode_get_child(tn, 2*i+1);
		put_child(t, tn, 2*i+1, NULL);

		BUG_ON(!right);

		size = tnode_child_length(left);
		for (j = 0; j < size; j++) {
			put_child(t, left, j, rtnl_dereference(inode->child[j]));
			put_child(t, right, j, rtnl_dereference(inode->child[j + size]));
		}
		put_child(t, tn, 2*i, resize(t, left));
		put_child(t, tn, 2*i+1, resize(t, right));

		tnode_free_safe(inode);
	}
	tnode_free_safe(oldtnode);
	return tn;
nomem:
	tnode_clean_free(tn);
	return ERR_PTR(-ENOMEM);
}

static struct tnode *halve(struct trie *t, struct tnode *tn)
{
	struct tnode *oldtnode = tn;
	struct rt_trie_node *left, *right;
	int i;
	int olen = tnode_child_length(tn);

	pr_debug("In halve\n");

	tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits - 1);

	if (!tn)
		return ERR_PTR(-ENOMEM);

	/*
	 * Preallocate and store tnodes before the actual work so we
	 * don't get into an inconsistent state if memory allocation
	 * fails. In case of failure we return the oldnode and halve
	 * of tnode is ignored.
	 */

	for (i = 0; i < olen; i += 2) {
		left = tnode_get_child(oldtnode, i);
		right = tnode_get_child(oldtnode, i+1);

		/* Two nonempty children */
		if (left && right) {
			struct tnode *newn;

			newn = tnode_new(left->key, tn->pos + tn->bits, 1);

			if (!newn)
				goto nomem;

			put_child(t, tn, i/2, (struct rt_trie_node *)newn);
		}

	}

	for (i = 0; i < olen; i += 2) {
		struct tnode *newBinNode;

		left = tnode_get_child(oldtnode, i);
		right = tnode_get_child(oldtnode, i+1);

		/* At least one of the children is empty */
		if (left == NULL) {
			if (right == NULL)    /* Both are empty */
				continue;
			put_child(t, tn, i/2, right);
			continue;
		}

		if (right == NULL) {
			put_child(t, tn, i/2, left);
			continue;
		}

		/* Two nonempty children */
		newBinNode = (struct tnode *) tnode_get_child(tn, i/2);
		put_child(t, tn, i/2, NULL);
		put_child(t, newBinNode, 0, left);
		put_child(t, newBinNode, 1, right);
		put_child(t, tn, i/2, resize(t, newBinNode));
	}
	tnode_free_safe(oldtnode);
	return tn;
nomem:
	tnode_clean_free(tn);
	return ERR_PTR(-ENOMEM);
}

/* readside must use rcu_read_lock currently dump routines
 via get_fa_head and dump */

static struct leaf_info *find_leaf_info(struct leaf *l, int plen)
{
	struct hlist_head *head = &l->list;
	struct hlist_node *node;
	struct leaf_info *li;

	hlist_for_each_entry_rcu(li, node, head, hlist)
		if (li->plen == plen)
			return li;

	return NULL;
}

static inline struct list_head *get_fa_head(struct leaf *l, int plen)
{
	struct leaf_info *li = find_leaf_info(l, plen);

	if (!li)
		return NULL;

	return &li->falh;
}

static void insert_leaf_info(struct hlist_head *head, struct leaf_info *new)
{
	struct leaf_info *li = NULL, *last = NULL;
	struct hlist_node *node;

	if (hlist_empty(head)) {
		hlist_add_head_rcu(&new->hlist, head);
	} else {
		hlist_for_each_entry(li, node, head, hlist) {
			if (new->plen > li->plen)
				break;

			last = li;
		}
		if (last)
			hlist_add_after_rcu(&last->hlist, &new->hlist);
		else
			hlist_add_before_rcu(&new->hlist, &li->hlist);
	}
}

/* rcu_read_lock needs to be hold by caller from readside */

static struct leaf *
fib_find_node(struct trie *t, u32 key)
{
	int pos;
	struct tnode *tn;
	struct rt_trie_node *n;

	pos = 0;
	n = rcu_dereference_rtnl(t->trie);

	while (n != NULL &&  NODE_TYPE(n) == T_TNODE) {
		tn = (struct tnode *) n;

		check_tnode(tn);

		if (tkey_sub_equals(tn->key, pos, tn->pos-pos, key)) {
			pos = tn->pos + tn->bits;
			n = tnode_get_child_rcu(tn,
						tkey_extract_bits(key,
								  tn->pos,
								  tn->bits));
		} else
			break;
	}
	/* Case we have found a leaf. Compare prefixes */

	if (n != NULL && IS_LEAF(n) && tkey_equals(key, n->key))
		return (struct leaf *)n;

	return NULL;
}

static void trie_rebalance(struct trie *t, struct tnode *tn)
{
	int wasfull;
	t_key cindex, key;
	struct tnode *tp;

	key = tn->key;

	while (tn != NULL && (tp = node_parent((struct rt_trie_node *)tn)) != NULL) {
		cindex = tkey_extract_bits(key, tp->pos, tp->bits);
		wasfull = tnode_full(tp, tnode_get_child(tp, cindex));
		tn = (struct tnode *)resize(t, tn);

		tnode_put_child_reorg(tp, cindex,
				      (struct rt_trie_node *)tn, wasfull);

		tp = node_parent((struct rt_trie_node *) tn);
		if (!tp)
			rcu_assign_pointer(t->trie, (struct rt_trie_node *)tn);

		tnode_free_flush();
		if (!tp)
			break;
		tn = tp;
	}

	/* Handle last (top) tnode */
	if (IS_TNODE(tn))
		tn = (struct tnode *)resize(t, tn);

	rcu_assign_pointer(t->trie, (struct rt_trie_node *)tn);
	tnode_free_flush();
}

/* only used from updater-side */

static struct list_head *fib_insert_node(struct trie *t, u32 key, int plen)
{
	int pos, newpos;
	struct tnode *tp = NULL, *tn = NULL;
	struct rt_trie_node *n;
	struct leaf *l;
	int missbit;
	struct list_head *fa_head = NULL;
	struct leaf_info *li;
	t_key cindex;

	pos = 0;
	n = rtnl_dereference(t->trie);

	/* If we point to NULL, stop. Either the tree is empty and we should
	 * just put a new leaf in if, or we have reached an empty child slot,
	 * and we should just put our new leaf in that.
	 * If we point to a T_TNODE, check if it matches our key. Note that
	 * a T_TNODE might be skipping any number of bits - its 'pos' need
	 * not be the parent's 'pos'+'bits'!
	 *
	 * If it does match the current key, get pos/bits from it, extract
	 * the index from our key, push the T_TNODE and walk the tree.
	 *
	 * If it doesn't, we have to replace it with a new T_TNODE.
	 *
	 * If we point to a T_LEAF, it might or might not have the same key
	 * as we do. If it does, just change the value, update the T_LEAF's
	 * value, and return it.
	 * If it doesn't, we need to replace it with a T_TNODE.
	 */

	while (n != NULL &&  NODE_TYPE(n) == T_TNODE) {
		tn = (struct tnode *) n;

		check_tnode(tn);

		if (tkey_sub_equals(tn->key, pos, tn->pos-pos, key)) {
			tp = tn;
			pos = tn->pos + tn->bits;
			n = tnode_get_child(tn,
					    tkey_extract_bits(key,
							      tn->pos,
							      tn->bits));

			BUG_ON(n && node_parent(n) != tn);
		} else
			break;
	}

	/*
	 * n  ----> NULL, LEAF or TNODE
	 *
	 * tp is n's (parent) ----> NULL or TNODE
	 */

	BUG_ON(tp && IS_LEAF(tp));

	/* Case 1: n is a leaf. Compare prefixes */

	if (n != NULL && IS_LEAF(n) && tkey_equals(key, n->key)) {
		l = (struct leaf *) n;
		li = leaf_info_new(plen);

		if (!li)
			return NULL;

		fa_head = &li->falh;
		insert_leaf_info(&l->list, li);
		goto done;
	}
	l = leaf_new();

	if (!l)
		return NULL;

	l->key = key;
	li = leaf_info_new(plen);

	if (!li) {
		free_leaf(l);
		return NULL;
	}

	fa_head = &li->falh;
	insert_leaf_info(&l->list, li);

	if (t->trie && n == NULL) {
		/* Case 2: n is NULL, and will just insert a new leaf */

		node_set_parent((struct rt_trie_node *)l, tp);

		cindex = tkey_extract_bits(key, tp->pos, tp->bits);
		put_child(t, tp, cindex, (struct rt_trie_node *)l);
	} else {
		/* Case 3: n is a LEAF or a TNODE and the key doesn't match. */
		/*
		 *  Add a new tnode here
		 *  first tnode need some special handling
		 */

		if (tp)
			pos = tp->pos+tp->bits;
		else
			pos = 0;

		if (n) {
			newpos = tkey_mismatch(key, pos, n->key);
			tn = tnode_new(n->key, newpos, 1);
		} else {
			newpos = 0;
			tn = tnode_new(key, newpos, 1); /* First tnode */
		}

		if (!tn) {
			free_leaf_info(li);
			free_leaf(l);
			return NULL;
		}

		node_set_parent((struct rt_trie_node *)tn, tp);

		missbit = tkey_extract_bits(key, newpos, 1);
		put_child(t, tn, missbit, (struct rt_trie_node *)l);
		put_child(t, tn, 1-missbit, n);

		if (tp) {
			cindex = tkey_extract_bits(key, tp->pos, tp->bits);
			put_child(t, tp, cindex, (struct rt_trie_node *)tn);
		} else {
			rcu_assign_pointer(t->trie, (struct rt_trie_node *)tn);
			tp = tn;
		}
	}

	if (tp && tp->pos + tp->bits > 32)
		pr_warn("fib_trie tp=%p pos=%d, bits=%d, key=%0x plen=%d\n",
			tp, tp->pos, tp->bits, key, plen);

	/* Rebalance the trie */

	trie_rebalance(t, tp);
done:
	return fa_head;
}

/*
 * Caller must hold RTNL.
 */
int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
{
	struct trie *t = (struct trie *) tb->tb_data;
	struct fib_alias *fa, *new_fa;
	struct list_head *fa_head = NULL;
	struct fib_info *fi;
	int plen = cfg->fc_dst_len;
	u8 tos = cfg->fc_tos;
	u32 key, mask;
	int err;
	struct leaf *l;

	if (plen > 32)
		return -EINVAL;

	key = ntohl(cfg->fc_dst);

	pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);

	mask = ntohl(inet_make_mask(plen));

	if (key & ~mask)
		return -EINVAL;

	key = key & mask;

	fi = fib_create_info(cfg);
	if (IS_ERR(fi)) {
		err = PTR_ERR(fi);
		goto err;
	}

	l = fib_find_node(t, key);
	fa = NULL;

	if (l) {
		fa_head = get_fa_head(l, plen);
		fa = fib_find_alias(fa_head, tos, fi->fib_priority);
	}

	/* Now fa, if non-NULL, points to the first fib alias
	 * with the same keys [prefix,tos,priority], if such key already
	 * exists or to the node before which we will insert new one.
	 *
	 * If fa is NULL, we will need to allocate a new one and
	 * insert to the head of f.
	 *
	 * If f is NULL, no fib node matched the destination key
	 * and we need to allocate a new one of those as well.
	 */

	if (fa && fa->fa_tos == tos &&
	    fa->fa_info->fib_priority == fi->fib_priority) {
		struct fib_alias *fa_first, *fa_match;

		err = -EEXIST;
		if (cfg->fc_nlflags & NLM_F_EXCL)
			goto out;

		/* We have 2 goals:
		 * 1. Find exact match for type, scope, fib_info to avoid
		 * duplicate routes
		 * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
		 */
		fa_match = NULL;
		fa_first = fa;
		fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
		list_for_each_entry_continue(fa, fa_head, fa_list) {
			if (fa->fa_tos != tos)
				break;
			if (fa->fa_info->fib_priority != fi->fib_priority)
				break;
			if (fa->fa_type == cfg->fc_type &&
			    fa->fa_info == fi) {
				fa_match = fa;
				break;
			}
		}

		if (cfg->fc_nlflags & NLM_F_REPLACE) {
			struct fib_info *fi_drop;
			u8 state;

			fa = fa_first;
			if (fa_match) {
				if (fa == fa_match)
					err = 0;
				goto out;
			}
			err = -ENOBUFS;
			new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
			if (new_fa == NULL)
				goto out;

			fi_drop = fa->fa_info;
			new_fa->fa_tos = fa->fa_tos;
			new_fa->fa_info = fi;
			new_fa->fa_type = cfg->fc_type;
			state = fa->fa_state;
			new_fa->fa_state = state & ~FA_S_ACCESSED;

			list_replace_rcu(&fa->fa_list, &new_fa->fa_list);
			alias_free_mem_rcu(fa);

			fib_release_info(fi_drop);
			if (state & FA_S_ACCESSED)
				rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);
			rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
				tb->tb_id, &cfg->fc_nlinfo, NLM_F_REPLACE);

			goto succeeded;
		}
		/* Error if we find a perfect match which
		 * uses the same scope, type, and nexthop
		 * information.
		 */
		if (fa_match)
			goto out;

		if (!(cfg->fc_nlflags & NLM_F_APPEND))
			fa = fa_first;
	}
	err = -ENOENT;
	if (!(cfg->fc_nlflags & NLM_F_CREATE))
		goto out;

	err = -ENOBUFS;
	new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
	if (new_fa == NULL)
		goto out;

	new_fa->fa_info = fi;
	new_fa->fa_tos = tos;
	new_fa->fa_type = cfg->fc_type;
	new_fa->fa_state = 0;
	/*
	 * Insert new entry to the list.
	 */

	if (!fa_head) {
		fa_head = fib_insert_node(t, key, plen);
		if (unlikely(!fa_head)) {
			err = -ENOMEM;
			goto out_free_new_fa;
		}
	}

	if (!plen)
		tb->tb_num_default++;

	list_add_tail_rcu(&new_fa->fa_list,
			  (fa ? &fa->fa_list : fa_head));

	rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);
	rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, tb->tb_id,
		  &cfg->fc_nlinfo, 0);
succeeded:
	return 0;

out_free_new_fa:
	kmem_cache_free(fn_alias_kmem, new_fa);
out:
	fib_release_info(fi);
err:
	return err;
}

/* should be called with rcu_read_lock */
static int check_leaf(struct fib_table *tb, struct trie *t, struct leaf *l,
		      t_key key,  const struct flowi4 *flp,
		      struct fib_result *res, int fib_flags)
{
	struct leaf_info *li;
	struct hlist_head *hhead = &l->list;
	struct hlist_node *node;

	hlist_for_each_entry_rcu(li, node, hhead, hlist) {
		struct fib_alias *fa;

		if (l->key != (key & li->mask_plen))
			continue;

		list_for_each_entry_rcu(fa, &li->falh, fa_list) {
			struct fib_info *fi = fa->fa_info;
			int nhsel, err;

			if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
				continue;
			if (fi->fib_dead)
				continue;
			if (fa->fa_info->fib_scope < flp->flowi4_scope)
				continue;
			fib_alias_accessed(fa);
			err = fib_props[fa->fa_type].error;
			if (err) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
				t->stats.semantic_match_passed++;
#endif
				return err;
			}
			if (fi->fib_flags & RTNH_F_DEAD)
				continue;
			for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
				const struct fib_nh *nh = &fi->fib_nh[nhsel];

				if (nh->nh_flags & RTNH_F_DEAD)
					continue;
				if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
					continue;

#ifdef CONFIG_IP_FIB_TRIE_STATS
				t->stats.semantic_match_passed++;
#endif
				res->prefixlen = li->plen;
				res->nh_sel = nhsel;
				res->type = fa->fa_type;
				res->scope = fa->fa_info->fib_scope;
				res->fi = fi;
				res->table = tb;
				res->fa_head = &li->falh;
				if (!(fib_flags & FIB_LOOKUP_NOREF))
					atomic_inc(&fi->fib_clntref);
				return 0;
			}
		}

#ifdef CONFIG_IP_FIB_TRIE_STATS
		t->stats.semantic_match_miss++;
#endif
	}

	return 1;
}

int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
		     struct fib_result *res, int fib_flags)
{
	struct trie *t = (struct trie *) tb->tb_data;
	int ret;
	struct rt_trie_node *n;
	struct tnode *pn;
	unsigned int pos, bits;
	t_key key = ntohl(flp->daddr);
	unsigned int chopped_off;
	t_key cindex = 0;
	unsigned int current_prefix_length = KEYLENGTH;
	struct tnode *cn;
	t_key pref_mismatch;

	rcu_read_lock();

	n = rcu_dereference(t->trie);
	if (!n)
		goto failed;

#ifdef CONFIG_IP_FIB_TRIE_STATS
	t->stats.gets++;
#endif

	/* Just a leaf? */
	if (IS_LEAF(n)) {
		ret = check_leaf(tb, t, (struct leaf *)n, key, flp, res, fib_flags);
		goto found;
	}

	pn = (struct tnode *) n;
	chopped_off = 0;

	while (pn) {
		pos = pn->pos;
		bits = pn->bits;

		if (!chopped_off)
			cindex = tkey_extract_bits(mask_pfx(key, current_prefix_length),
						   pos, bits);

		n = tnode_get_child_rcu(pn, cindex);

		if (n == NULL) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
			t->stats.null_node_hit++;
#endif
			goto backtrace;
		}

		if (IS_LEAF(n)) {
			ret = check_leaf(tb, t, (struct leaf *)n, key, flp, res, fib_flags);
			if (ret > 0)
				goto backtrace;
			goto found;
		}

		cn = (struct tnode *)n;

		/*
		 * It's a tnode, and we can do some extra checks here if we
		 * like, to avoid descending into a dead-end branch.
		 * This tnode is in the parent's child array at index
		 * key[p_pos..p_pos+p_bits] but potentially with some bits
		 * chopped off, so in reality the index may be just a
		 * subprefix, padded with zero at the end.
		 * We can also take a look at any skipped bits in this
		 * tnode - everything up to p_pos is supposed to be ok,
		 * and the non-chopped bits of the index (se previous
		 * paragraph) are also guaranteed ok, but the rest is
		 * considered unknown.
		 *
		 * The skipped bits are key[pos+bits..cn->pos].
		 */

		/* If current_prefix_length < pos+bits, we are already doing
		 * actual prefix  matching, which means everything from
		 * pos+(bits-chopped_off) onward must be zero along some
		 * branch of this subtree - otherwise there is *no* valid
		 * prefix present. Here we can only check the skipped
		 * bits. Remember, since we have already indexed into the
		 * parent's child array, we know that the bits we chopped of
		 * *are* zero.
		 */

		/* NOTA BENE: Checking only skipped bits
		   for the new node here */

		if (current_prefix_length < pos+bits) {
			if (tkey_extract_bits(cn->key, current_prefix_length,
						cn->pos - current_prefix_length)
			    || !(cn->child[0]))
				goto backtrace;
		}

		/*
		 * If chopped_off=0, the index is fully validated and we
		 * only need to look at the skipped bits for this, the new,
		 * tnode. What we actually want to do is to find out if
		 * these skipped bits match our key perfectly, or if we will
		 * have to count on finding a matching prefix further down,
		 * because if we do, we would like to have some way of
		 * verifying the existence of such a prefix at this point.
		 */

		/* The only thing we can do at this point is to verify that
		 * any such matching prefix can indeed be a prefix to our
		 * key, and if the bits in the node we are inspecting that
		 * do not match our key are not ZERO, this cannot be true.
		 * Thus, find out where there is a mismatch (before cn->pos)
		 * and verify that all the mismatching bits are zero in the
		 * new tnode's key.
		 */

		/*
		 * Note: We aren't very concerned about the piece of
		 * the key that precede pn->pos+pn->bits, since these
		 * have already been checked. The bits after cn->pos
		 * aren't checked since these are by definition
		 * "unknown" at this point. Thus, what we want to see
		 * is if we are about to enter the "prefix matching"
		 * state, and in that case verify that the skipped
		 * bits that will prevail throughout this subtree are
		 * zero, as they have to be if we are to find a
		 * matching prefix.
		 */

		pref_mismatch = mask_pfx(cn->key ^ key, cn->pos);

		/*
		 * In short: If skipped bits in this node do not match
		 * the search key, enter the "prefix matching"
		 * state.directly.
		 */
		if (pref_mismatch) {
			int mp = KEYLENGTH - fls(pref_mismatch);

			if (tkey_extract_bits(cn->key, mp, cn->pos - mp) != 0)
				goto backtrace;

			if (current_prefix_length >= cn->pos)
				current_prefix_length = mp;
		}

		pn = (struct tnode *)n; /* Descend */
		chopped_off = 0;
		continue;

backtrace:
		chopped_off++;

		/* As zero don't change the child key (cindex) */
		while ((chopped_off <= pn->bits)
		       && !(cindex & (1<<(chopped_off-1))))
			chopped_off++;

		/* Decrease current_... with bits chopped off */
		if (current_prefix_length > pn->pos + pn->bits - chopped_off)
			current_prefix_length = pn->pos + pn->bits
				- chopped_off;

		/*
		 * Either we do the actual chop off according or if we have
		 * chopped off all bits in this tnode walk up to our parent.
		 */

		if (chopped_off <= pn->bits) {
			cindex &= ~(1 << (chopped_off-1));
		} else {
			struct tnode *parent = node_parent_rcu((struct rt_trie_node *) pn);
			if (!parent)
				goto failed;

			/* Get Child's index */
			cindex = tkey_extract_bits(pn->key, parent->pos, parent->bits);
			pn = parent;
			chopped_off = 0;

#ifdef CONFIG_IP_FIB_TRIE_STATS
			t->stats.backtrack++;
#endif
			goto backtrace;
		}
	}
failed:
	ret = 1;
found:
	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(fib_table_lookup);

/*
 * Remove the leaf and return parent.
 */
static void trie_leaf_remove(struct trie *t, struct leaf *l)
{
	struct tnode *tp = node_parent((struct rt_trie_node *) l);

	pr_debug("entering trie_leaf_remove(%p)\n", l);

	if (tp) {
		t_key cindex = tkey_extract_bits(l->key, tp->pos, tp->bits);
		put_child(t, tp, cindex, NULL);
		trie_rebalance(t, tp);
	} else
		RCU_INIT_POINTER(t->trie, NULL);

	free_leaf(l);
}

/*
 * Caller must hold RTNL.
 */
int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
{
	struct trie *t = (struct trie *) tb->tb_data;
	u32 key, mask;
	int plen = cfg->fc_dst_len;
	u8 tos = cfg->fc_tos;
	struct fib_alias *fa, *fa_to_delete;
	struct list_head *fa_head;
	struct leaf *l;
	struct leaf_info *li;

	if (plen > 32)
		return -EINVAL;

	key = ntohl(cfg->fc_dst);
	mask = ntohl(inet_make_mask(plen));

	if (key & ~mask)
		return -EINVAL;

	key = key & mask;
	l = fib_find_node(t, key);

	if (!l)
		return -ESRCH;

	fa_head = get_fa_head(l, plen);
	fa = fib_find_alias(fa_head, tos, 0);

	if (!fa)
		return -ESRCH;

	pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);

	fa_to_delete = NULL;
	fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
	list_for_each_entry_continue(fa, fa_head, fa_list) {
		struct fib_info *fi = fa->fa_info;

		if (fa->fa_tos != tos)
			break;

		if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
		    (cfg->fc_scope == RT_SCOPE_NOWHERE ||
		     fa->fa_info->fib_scope == cfg->fc_scope) &&
		    (!cfg->fc_prefsrc ||
		     fi->fib_prefsrc == cfg->fc_prefsrc) &&
		    (!cfg->fc_protocol ||
		     fi->fib_protocol == cfg->fc_protocol) &&
		    fib_nh_match(cfg, fi) == 0) {
			fa_to_delete = fa;
			break;
		}
	}

	if (!fa_to_delete)
		return -ESRCH;

	fa = fa_to_delete;
	rtmsg_fib(RTM_DELROUTE, htonl(key), fa, plen, tb->tb_id,
		  &cfg->fc_nlinfo, 0);

	l = fib_find_node(t, key);
	li = find_leaf_info(l, plen);

	list_del_rcu(&fa->fa_list);

	if (!plen)
		tb->tb_num_default--;

	if (list_empty(fa_head)) {
		hlist_del_rcu(&li->hlist);
		free_leaf_info(li);
	}

	if (hlist_empty(&l->list))
		trie_leaf_remove(t, l);

	if (fa->fa_state & FA_S_ACCESSED)
		rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);

	fib_release_info(fa->fa_info);
	alias_free_mem_rcu(fa);
	return 0;
}

static int trie_flush_list(struct list_head *head)
{
	struct fib_alias *fa, *fa_node;
	int found = 0;

	list_for_each_entry_safe(fa, fa_node, head, fa_list) {
		struct fib_info *fi = fa->fa_info;

		if (fi && (fi->fib_flags & RTNH_F_DEAD)) {
			list_del_rcu(&fa->fa_list);
			fib_release_info(fa->fa_info);
			alias_free_mem_rcu(fa);
			found++;
		}
	}
	return found;
}

static int trie_flush_leaf(struct leaf *l)
{
	int found = 0;
	struct hlist_head *lih = &l->list;
	struct hlist_node *node, *tmp;
	struct leaf_info *li = NULL;

	hlist_for_each_entry_safe(li, node, tmp, lih, hlist) {
		found += trie_flush_list(&li->falh);

		if (list_empty(&li->falh)) {
			hlist_del_rcu(&li->hlist);
			free_leaf_info(li);
		}
	}
	return found;
}

/*
 * Scan for the next right leaf starting at node p->child[idx]
 * Since we have back pointer, no recursion necessary.
 */
static struct leaf *leaf_walk_rcu(struct tnode *p, struct rt_trie_node *c)
{
	do {
		t_key idx;

		if (c)
			idx = tkey_extract_bits(c->key, p->pos, p->bits) + 1;
		else
			idx = 0;

		while (idx < 1u << p->bits) {
			c = tnode_get_child_rcu(p, idx++);
			if (!c)
				continue;

			if (IS_LEAF(c)) {
				prefetch(rcu_dereference_rtnl(p->child[idx]));
				return (struct leaf *) c;
			}

			/* Rescan start scanning in new node */
			p = (struct tnode *) c;
			idx = 0;
		}

		/* Node empty, walk back up to parent */
		c = (struct rt_trie_node *) p;
	} while ((p = node_parent_rcu(c)) != NULL);

	return NULL; /* Root of trie */
}

static struct leaf *trie_firstleaf(struct trie *t)
{
	struct tnode *n = (struct tnode *)rcu_dereference_rtnl(t->trie);

	if (!n)
		return NULL;

	if (IS_LEAF(n))          /* trie is just a leaf */
		return (struct leaf *) n;

	return leaf_walk_rcu(n, NULL);
}

static struct leaf *trie_nextleaf(struct leaf *l)
{
	struct rt_trie_node *c = (struct rt_trie_node *) l;
	struct tnode *p = node_parent_rcu(c);

	if (!p)
		return NULL;	/* trie with just one leaf */

	return leaf_walk_rcu(p, c);
}

static struct leaf *trie_leafindex(struct trie *t, int index)
{
	struct leaf *l = trie_firstleaf(t);

	while (l && index-- > 0)
		l = trie_nextleaf(l);

	return l;
}


/*
 * Caller must hold RTNL.
 */
int fib_table_flush(struct fib_table *tb)
{
	struct trie *t = (struct trie *) tb->tb_data;
	struct leaf *l, *ll = NULL;
	int found = 0;

	for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) {
		found += trie_flush_leaf(l);

		if (ll && hlist_empty(&ll->list))
			trie_leaf_remove(t, ll);
		ll = l;
	}

	if (ll && hlist_empty(&ll->list))
		trie_leaf_remove(t, ll);

	pr_debug("trie_flush found=%d\n", found);
	return found;
}

void fib_free_table(struct fib_table *tb)
{
	kfree(tb);
}

static int fn_trie_dump_fa(t_key key, int plen, struct list_head *fah,
			   struct fib_table *tb,
			   struct sk_buff *skb, struct netlink_callback *cb)
{
	int i, s_i;
	struct fib_alias *fa;
	__be32 xkey = htonl(key);

	s_i = cb->args[5];
	i = 0;

	/* rcu_read_lock is hold by caller */

	list_for_each_entry_rcu(fa, fah, fa_list) {
		if (i < s_i) {
			i++;
			continue;
		}

		if (fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
				  cb->nlh->nlmsg_seq,
				  RTM_NEWROUTE,
				  tb->tb_id,
				  fa->fa_type,
				  xkey,
				  plen,
				  fa->fa_tos,
				  fa->fa_info, NLM_F_MULTI) < 0) {
			cb->args[5] = i;
			return -1;
		}
		i++;
	}
	cb->args[5] = i;
	return skb->len;
}

static int fn_trie_dump_leaf(struct leaf *l, struct fib_table *tb,
			struct sk_buff *skb, struct netlink_callback *cb)
{
	struct leaf_info *li;
	struct hlist_node *node;
	int i, s_i;

	s_i = cb->args[4];
	i = 0;

	/* rcu_read_lock is hold by caller */
	hlist_for_each_entry_rcu(li, node, &l->list, hlist) {
		if (i < s_i) {
			i++;
			continue;
		}

		if (i > s_i)
			cb->args[5] = 0;

		if (list_empty(&li->falh))
			continue;

		if (fn_trie_dump_fa(l->key, li->plen, &li->falh, tb, skb, cb) < 0) {
			cb->args[4] = i;
			return -1;
		}
		i++;
	}

	cb->args[4] = i;
	return skb->len;
}

int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
		   struct netlink_callback *cb)
{
	struct leaf *l;
	struct trie *t = (struct trie *) tb->tb_data;
	t_key key = cb->args[2];
	int count = cb->args[3];

	rcu_read_lock();
	/* Dump starting at last key.
	 * Note: 0.0.0.0/0 (ie default) is first key.
	 */
	if (count == 0)
		l = trie_firstleaf(t);
	else {
		/* Normally, continue from last key, but if that is missing
		 * fallback to using slow rescan
		 */
		l = fib_find_node(t, key);
		if (!l)
			l = trie_leafindex(t, count);
	}

	while (l) {
		cb->args[2] = l->key;
		if (fn_trie_dump_leaf(l, tb, skb, cb) < 0) {
			cb->args[3] = count;
			rcu_read_unlock();
			return -1;
		}

		++count;
		l = trie_nextleaf(l);
		memset(&cb->args[4], 0,
		       sizeof(cb->args) - 4*sizeof(cb->args[0]));
	}
	cb->args[3] = count;
	rcu_read_unlock();

	return skb->len;
}

void __init fib_trie_init(void)
{
	fn_alias_kmem = kmem_cache_create("ip_fib_alias",
					  sizeof(struct fib_alias),
					  0, SLAB_PANIC, NULL);

	trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
					   max(sizeof(struct leaf),
					       sizeof(struct leaf_info)),
					   0, SLAB_PANIC, NULL);
}


struct fib_table *fib_trie_table(u32 id)
{
	struct fib_table *tb;
	struct trie *t;

	tb = kmalloc(sizeof(struct fib_table) + sizeof(struct trie),
		     GFP_KERNEL);
	if (tb == NULL)
		return NULL;

	tb->tb_id = id;
	tb->tb_default = -1;
	tb->tb_num_default = 0;

	t = (struct trie *) tb->tb_data;
	memset(t, 0, sizeof(*t));

	return tb;
}

#ifdef CONFIG_PROC_FS
/* Depth first Trie walk iterator */
struct fib_trie_iter {
	struct seq_net_private p;
	struct fib_table *tb;
	struct tnode *tnode;
	unsigned int index;
	unsigned int depth;
};

static struct rt_trie_node *fib_trie_get_next(struct fib_trie_iter *iter)
{
	struct tnode *tn = iter->tnode;
	unsigned int cindex = iter->index;
	struct tnode *p;

	/* A single entry routing table */
	if (!tn)
		return NULL;

	pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
		 iter->tnode, iter->index, iter->depth);
rescan:
	while (cindex < (1<<tn->bits)) {
		struct rt_trie_node *n = tnode_get_child_rcu(tn, cindex);

		if (n) {
			if (IS_LEAF(n)) {
				iter->tnode = tn;
				iter->index = cindex + 1;
			} else {
				/* push down one level */
				iter->tnode = (struct tnode *) n;
				iter->index = 0;
				++iter->depth;
			}
			return n;
		}

		++cindex;
	}

	/* Current node exhausted, pop back up */
	p = node_parent_rcu((struct rt_trie_node *)tn);
	if (p) {
		cindex = tkey_extract_bits(tn->key, p->pos, p->bits)+1;
		tn = p;
		--iter->depth;
		goto rescan;
	}

	/* got root? */
	return NULL;
}

static struct rt_trie_node *fib_trie_get_first(struct fib_trie_iter *iter,
				       struct trie *t)
{
	struct rt_trie_node *n;

	if (!t)
		return NULL;

	n = rcu_dereference(t->trie);
	if (!n)
		return NULL;

	if (IS_TNODE(n)) {
		iter->tnode = (struct tnode *) n;
		iter->index = 0;
		iter->depth = 1;
	} else {
		iter->tnode = NULL;
		iter->index = 0;
		iter->depth = 0;
	}

	return n;
}

static void trie_collect_stats(struct trie *t, struct trie_stat *s)
{
	struct rt_trie_node *n;
	struct fib_trie_iter iter;

	memset(s, 0, sizeof(*s));

	rcu_read_lock();
	for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
		if (IS_LEAF(n)) {
			struct leaf *l = (struct leaf *)n;
			struct leaf_info *li;
			struct hlist_node *tmp;

			s->leaves++;
			s->totdepth += iter.depth;
			if (iter.depth > s->maxdepth)
				s->maxdepth = iter.depth;

			hlist_for_each_entry_rcu(li, tmp, &l->list, hlist)
				++s->prefixes;
		} else {
			const struct tnode *tn = (const struct tnode *) n;
			int i;

			s->tnodes++;
			if (tn->bits < MAX_STAT_DEPTH)
				s->nodesizes[tn->bits]++;

			for (i = 0; i < (1<<tn->bits); i++)
				if (!tn->child[i])
					s->nullpointers++;
		}
	}
	rcu_read_unlock();
}

/*
 *	This outputs /proc/net/fib_triestats
 */
static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
{
	unsigned int i, max, pointers, bytes, avdepth;

	if (stat->leaves)
		avdepth = stat->totdepth*100 / stat->leaves;
	else
		avdepth = 0;

	seq_printf(seq, "\tAver depth:     %u.%02d\n",
		   avdepth / 100, avdepth % 100);
	seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);

	seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
	bytes = sizeof(struct leaf) * stat->leaves;

	seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
	bytes += sizeof(struct leaf_info) * stat->prefixes;

	seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
	bytes += sizeof(struct tnode) * stat->tnodes;

	max = MAX_STAT_DEPTH;
	while (max > 0 && stat->nodesizes[max-1] == 0)
		max--;

	pointers = 0;
	for (i = 1; i <= max; i++)
		if (stat->nodesizes[i] != 0) {
			seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
			pointers += (1<<i) * stat->nodesizes[i];
		}
	seq_putc(seq, '\n');
	seq_printf(seq, "\tPointers: %u\n", pointers);

	bytes += sizeof(struct rt_trie_node *) * pointers;
	seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
	seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
}

#ifdef CONFIG_IP_FIB_TRIE_STATS
static void trie_show_usage(struct seq_file *seq,
			    const struct trie_use_stats *stats)
{
	seq_printf(seq, "\nCounters:\n---------\n");
	seq_printf(seq, "gets = %u\n", stats->gets);
	seq_printf(seq, "backtracks = %u\n", stats->backtrack);
	seq_printf(seq, "semantic match passed = %u\n",
		   stats->semantic_match_passed);
	seq_printf(seq, "semantic match miss = %u\n",
		   stats->semantic_match_miss);
	seq_printf(seq, "null node hit= %u\n", stats->null_node_hit);
	seq_printf(seq, "skipped node resize = %u\n\n",
		   stats->resize_node_skipped);
}
#endif /*  CONFIG_IP_FIB_TRIE_STATS */

static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
{
	if (tb->tb_id == RT_TABLE_LOCAL)
		seq_puts(seq, "Local:\n");
	else if (tb->tb_id == RT_TABLE_MAIN)
		seq_puts(seq, "Main:\n");
	else
		seq_printf(seq, "Id %d:\n", tb->tb_id);
}


static int fib_triestat_seq_show(struct seq_file *seq, void *v)
{
	struct net *net = (struct net *)seq->private;
	unsigned int h;

	seq_printf(seq,
		   "Basic info: size of leaf:"
		   " %Zd bytes, size of tnode: %Zd bytes.\n",
		   sizeof(struct leaf), sizeof(struct tnode));

	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
		struct hlist_node *node;
		struct fib_table *tb;

		hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
			struct trie *t = (struct trie *) tb->tb_data;
			struct trie_stat stat;

			if (!t)
				continue;

			fib_table_print(seq, tb);

			trie_collect_stats(t, &stat);
			trie_show_stats(seq, &stat);
#ifdef CONFIG_IP_FIB_TRIE_STATS
			trie_show_usage(seq, &t->stats);
#endif
		}
	}

	return 0;
}

static int fib_triestat_seq_open(struct inode *inode, struct file *file)
{
	return single_open_net(inode, file, fib_triestat_seq_show);
}

static const struct file_operations fib_triestat_fops = {
	.owner	= THIS_MODULE,
	.open	= fib_triestat_seq_open,
	.read	= seq_read,
	.llseek	= seq_lseek,
	.release = single_release_net,
};

static struct rt_trie_node *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
{
	struct fib_trie_iter *iter = seq->private;
	struct net *net = seq_file_net(seq);
	loff_t idx = 0;
	unsigned int h;

	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
		struct hlist_node *node;
		struct fib_table *tb;

		hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
			struct rt_trie_node *n;

			for (n = fib_trie_get_first(iter,
						    (struct trie *) tb->tb_data);
			     n; n = fib_trie_get_next(iter))
				if (pos == idx++) {
					iter->tb = tb;
					return n;
				}
		}
	}

	return NULL;
}

static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(RCU)
{
	rcu_read_lock();
	return fib_trie_get_idx(seq, *pos);
}

static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct fib_trie_iter *iter = seq->private;
	struct net *net = seq_file_net(seq);
	struct fib_table *tb = iter->tb;
	struct hlist_node *tb_node;
	unsigned int h;
	struct rt_trie_node *n;

	++*pos;
	/* next node in same table */
	n = fib_trie_get_next(iter);
	if (n)
		return n;

	/* walk rest of this hash chain */
	h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
	while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
		tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
		n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
		if (n)
			goto found;
	}

	/* new hash chain */
	while (++h < FIB_TABLE_HASHSZ) {
		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
		hlist_for_each_entry_rcu(tb, tb_node, head, tb_hlist) {
			n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
			if (n)
				goto found;
		}
	}
	return NULL;

found:
	iter->tb = tb;
	return n;
}

static void fib_trie_seq_stop(struct seq_file *seq, void *v)
	__releases(RCU)
{
	rcu_read_unlock();
}

static void seq_indent(struct seq_file *seq, int n)
{
	while (n-- > 0)
		seq_puts(seq, "   ");
}

static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
{
	switch (s) {
	case RT_SCOPE_UNIVERSE: return "universe";
	case RT_SCOPE_SITE:	return "site";
	case RT_SCOPE_LINK:	return "link";
	case RT_SCOPE_HOST:	return "host";
	case RT_SCOPE_NOWHERE:	return "nowhere";
	default:
		snprintf(buf, len, "scope=%d", s);
		return buf;
	}
}

static const char *const rtn_type_names[__RTN_MAX] = {
	[RTN_UNSPEC] = "UNSPEC",
	[RTN_UNICAST] = "UNICAST",
	[RTN_LOCAL] = "LOCAL",
	[RTN_BROADCAST] = "BROADCAST",
	[RTN_ANYCAST] = "ANYCAST",
	[RTN_MULTICAST] = "MULTICAST",
	[RTN_BLACKHOLE] = "BLACKHOLE",
	[RTN_UNREACHABLE] = "UNREACHABLE",
	[RTN_PROHIBIT] = "PROHIBIT",
	[RTN_THROW] = "THROW",
	[RTN_NAT] = "NAT",
	[RTN_XRESOLVE] = "XRESOLVE",
};

static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
{
	if (t < __RTN_MAX && rtn_type_names[t])
		return rtn_type_names[t];
	snprintf(buf, len, "type %u", t);
	return buf;
}

/* Pretty print the trie */
static int fib_trie_seq_show(struct seq_file *seq, void *v)
{
	const struct fib_trie_iter *iter = seq->private;
	struct rt_trie_node *n = v;

	if (!node_parent_rcu(n))
		fib_table_print(seq, iter->tb);

	if (IS_TNODE(n)) {
		struct tnode *tn = (struct tnode *) n;
		__be32 prf = htonl(mask_pfx(tn->key, tn->pos));

		seq_indent(seq, iter->depth-1);
		seq_printf(seq, "  +-- %pI4/%d %d %d %d\n",
			   &prf, tn->pos, tn->bits, tn->full_children,
			   tn->empty_children);

	} else {
		struct leaf *l = (struct leaf *) n;
		struct leaf_info *li;
		struct hlist_node *node;
		__be32 val = htonl(l->key);

		seq_indent(seq, iter->depth);
		seq_printf(seq, "  |-- %pI4\n", &val);

		hlist_for_each_entry_rcu(li, node, &l->list, hlist) {
			struct fib_alias *fa;

			list_for_each_entry_rcu(fa, &li->falh, fa_list) {
				char buf1[32], buf2[32];

				seq_indent(seq, iter->depth+1);
				seq_printf(seq, "  /%d %s %s", li->plen,
					   rtn_scope(buf1, sizeof(buf1),
						     fa->fa_info->fib_scope),
					   rtn_type(buf2, sizeof(buf2),
						    fa->fa_type));
				if (fa->fa_tos)
					seq_printf(seq, " tos=%d", fa->fa_tos);
				seq_putc(seq, '\n');
			}
		}
	}

	return 0;
}

static const struct seq_operations fib_trie_seq_ops = {
	.start  = fib_trie_seq_start,
	.next   = fib_trie_seq_next,
	.stop   = fib_trie_seq_stop,
	.show   = fib_trie_seq_show,
};

static int fib_trie_seq_open(struct inode *inode, struct file *file)
{
	return seq_open_net(inode, file, &fib_trie_seq_ops,
			    sizeof(struct fib_trie_iter));
}

static const struct file_operations fib_trie_fops = {
	.owner  = THIS_MODULE,
	.open   = fib_trie_seq_open,
	.read   = seq_read,
	.llseek = seq_lseek,
	.release = seq_release_net,
};

struct fib_route_iter {
	struct seq_net_private p;
	struct trie *main_trie;
	loff_t	pos;
	t_key	key;
};

static struct leaf *fib_route_get_idx(struct fib_route_iter *iter, loff_t pos)
{
	struct leaf *l = NULL;
	struct trie *t = iter->main_trie;

	/* use cache location of last found key */
	if (iter->pos > 0 && pos >= iter->pos && (l = fib_find_node(t, iter->key)))
		pos -= iter->pos;
	else {
		iter->pos = 0;
		l = trie_firstleaf(t);
	}

	while (l && pos-- > 0) {
		iter->pos++;
		l = trie_nextleaf(l);
	}

	if (l)
		iter->key = pos;	/* remember it */
	else
		iter->pos = 0;		/* forget it */

	return l;
}

static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(RCU)
{
	struct fib_route_iter *iter = seq->private;
	struct fib_table *tb;

	rcu_read_lock();
	tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
	if (!tb)
		return NULL;

	iter->main_trie = (struct trie *) tb->tb_data;
	if (*pos == 0)
		return SEQ_START_TOKEN;
	else
		return fib_route_get_idx(iter, *pos - 1);
}

static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct fib_route_iter *iter = seq->private;
	struct leaf *l = v;

	++*pos;
	if (v == SEQ_START_TOKEN) {
		iter->pos = 0;
		l = trie_firstleaf(iter->main_trie);
	} else {
		iter->pos++;
		l = trie_nextleaf(l);
	}

	if (l)
		iter->key = l->key;
	else
		iter->pos = 0;
	return l;
}

static void fib_route_seq_stop(struct seq_file *seq, void *v)
	__releases(RCU)
{
	rcu_read_unlock();
}

static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
{
	unsigned int flags = 0;

	if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
		flags = RTF_REJECT;
	if (fi && fi->fib_nh->nh_gw)
		flags |= RTF_GATEWAY;
	if (mask == htonl(0xFFFFFFFF))
		flags |= RTF_HOST;
	flags |= RTF_UP;
	return flags;
}

/*
 *	This outputs /proc/net/route.
 *	The format of the file is not supposed to be changed
 *	and needs to be same as fib_hash output to avoid breaking
 *	legacy utilities
 */
static int fib_route_seq_show(struct seq_file *seq, void *v)
{
	struct leaf *l = v;
	struct leaf_info *li;
	struct hlist_node *node;

	if (v == SEQ_START_TOKEN) {
		seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
			   "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
			   "\tWindow\tIRTT");
		return 0;
	}

	hlist_for_each_entry_rcu(li, node, &l->list, hlist) {
		struct fib_alias *fa;
		__be32 mask, prefix;

		mask = inet_make_mask(li->plen);
		prefix = htonl(l->key);

		list_for_each_entry_rcu(fa, &li->falh, fa_list) {
			const struct fib_info *fi = fa->fa_info;
			unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
			int len;

			if (fa->fa_type == RTN_BROADCAST
			    || fa->fa_type == RTN_MULTICAST)
				continue;

			if (fi)
				seq_printf(seq,
					 "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
					 "%d\t%08X\t%d\t%u\t%u%n",
					 fi->fib_dev ? fi->fib_dev->name : "*",
					 prefix,
					 fi->fib_nh->nh_gw, flags, 0, 0,
					 fi->fib_priority,
					 mask,
					 (fi->fib_advmss ?
					  fi->fib_advmss + 40 : 0),
					 fi->fib_window,
					 fi->fib_rtt >> 3, &len);
			else
				seq_printf(seq,
					 "*\t%08X\t%08X\t%04X\t%d\t%u\t"
					 "%d\t%08X\t%d\t%u\t%u%n",
					 prefix, 0, flags, 0, 0, 0,
					 mask, 0, 0, 0, &len);

			seq_printf(seq, "%*s\n", 127 - len, "");
		}
	}

	return 0;
}

static const struct seq_operations fib_route_seq_ops = {
	.start  = fib_route_seq_start,
	.next   = fib_route_seq_next,
	.stop   = fib_route_seq_stop,
	.show   = fib_route_seq_show,
};

static int fib_route_seq_open(struct inode *inode, struct file *file)
{
	return seq_open_net(inode, file, &fib_route_seq_ops,
			    sizeof(struct fib_route_iter));
}

static const struct file_operations fib_route_fops = {
	.owner  = THIS_MODULE,
	.open   = fib_route_seq_open,
	.read   = seq_read,
	.llseek = seq_lseek,
	.release = seq_release_net,
};

int __net_init fib_proc_init(struct net *net)
{
	if (!proc_net_fops_create(net, "fib_trie", S_IRUGO, &fib_trie_fops))
		goto out1;

	if (!proc_net_fops_create(net, "fib_triestat", S_IRUGO,
				  &fib_triestat_fops))
		goto out2;

	if (!proc_net_fops_create(net, "route", S_IRUGO, &fib_route_fops))
		goto out3;

	return 0;

out3:
	proc_net_remove(net, "fib_triestat");
out2:
	proc_net_remove(net, "fib_trie");
out1:
	return -ENOMEM;
}

void __net_exit fib_proc_exit(struct net *net)
{
	proc_net_remove(net, "fib_trie");
	proc_net_remove(net, "fib_triestat");
	proc_net_remove(net, "route");
}

#endif /* CONFIG_PROC_FS */