summaryrefslogtreecommitdiffstats
path: root/net/tipc/link.c
blob: fb72031228c98f8fcf2919981e600202baf86301 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
/*
 * net/tipc/link.c: TIPC link code
 *
 * Copyright (c) 1996-2007, 2012-2016, Ericsson AB
 * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "subscr.h"
#include "link.h"
#include "bcast.h"
#include "socket.h"
#include "name_distr.h"
#include "discover.h"
#include "netlink.h"
#include "monitor.h"
#include "trace.h"
#include "crypto.h"

#include <linux/pkt_sched.h>

struct tipc_stats {
	u32 sent_pkts;
	u32 recv_pkts;
	u32 sent_states;
	u32 recv_states;
	u32 sent_probes;
	u32 recv_probes;
	u32 sent_nacks;
	u32 recv_nacks;
	u32 sent_acks;
	u32 sent_bundled;
	u32 sent_bundles;
	u32 recv_bundled;
	u32 recv_bundles;
	u32 retransmitted;
	u32 sent_fragmented;
	u32 sent_fragments;
	u32 recv_fragmented;
	u32 recv_fragments;
	u32 link_congs;		/* # port sends blocked by congestion */
	u32 deferred_recv;
	u32 duplicates;
	u32 max_queue_sz;	/* send queue size high water mark */
	u32 accu_queue_sz;	/* used for send queue size profiling */
	u32 queue_sz_counts;	/* used for send queue size profiling */
	u32 msg_length_counts;	/* used for message length profiling */
	u32 msg_lengths_total;	/* used for message length profiling */
	u32 msg_length_profile[7]; /* used for msg. length profiling */
};

/**
 * struct tipc_link - TIPC link data structure
 * @addr: network address of link's peer node
 * @name: link name character string
 * @media_addr: media address to use when sending messages over link
 * @timer: link timer
 * @net: pointer to namespace struct
 * @refcnt: reference counter for permanent references (owner node & timer)
 * @peer_session: link session # being used by peer end of link
 * @peer_bearer_id: bearer id used by link's peer endpoint
 * @bearer_id: local bearer id used by link
 * @tolerance: minimum link continuity loss needed to reset link [in ms]
 * @abort_limit: # of unacknowledged continuity probes needed to reset link
 * @state: current state of link FSM
 * @peer_caps: bitmap describing capabilities of peer node
 * @silent_intv_cnt: # of timer intervals without any reception from peer
 * @proto_msg: template for control messages generated by link
 * @pmsg: convenience pointer to "proto_msg" field
 * @priority: current link priority
 * @net_plane: current link network plane ('A' through 'H')
 * @mon_state: cookie with information needed by link monitor
 * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
 * @exp_msg_count: # of tunnelled messages expected during link changeover
 * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
 * @mtu: current maximum packet size for this link
 * @advertised_mtu: advertised own mtu when link is being established
 * @transmitq: queue for sent, non-acked messages
 * @backlogq: queue for messages waiting to be sent
 * @snt_nxt: next sequence number to use for outbound messages
 * @ackers: # of peers that needs to ack each packet before it can be released
 * @acked: # last packet acked by a certain peer. Used for broadcast.
 * @rcv_nxt: next sequence number to expect for inbound messages
 * @deferred_queue: deferred queue saved OOS b'cast message received from node
 * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
 * @inputq: buffer queue for messages to be delivered upwards
 * @namedq: buffer queue for name table messages to be delivered upwards
 * @next_out: ptr to first unsent outbound message in queue
 * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
 * @long_msg_seq_no: next identifier to use for outbound fragmented messages
 * @reasm_buf: head of partially reassembled inbound message fragments
 * @bc_rcvr: marks that this is a broadcast receiver link
 * @stats: collects statistics regarding link activity
 */
struct tipc_link {
	u32 addr;
	char name[TIPC_MAX_LINK_NAME];
	struct net *net;

	/* Management and link supervision data */
	u16 peer_session;
	u16 session;
	u16 snd_nxt_state;
	u16 rcv_nxt_state;
	u32 peer_bearer_id;
	u32 bearer_id;
	u32 tolerance;
	u32 abort_limit;
	u32 state;
	u16 peer_caps;
	bool in_session;
	bool active;
	u32 silent_intv_cnt;
	char if_name[TIPC_MAX_IF_NAME];
	u32 priority;
	char net_plane;
	struct tipc_mon_state mon_state;
	u16 rst_cnt;

	/* Failover/synch */
	u16 drop_point;
	struct sk_buff *failover_reasm_skb;
	struct sk_buff_head failover_deferdq;

	/* Max packet negotiation */
	u16 mtu;
	u16 advertised_mtu;

	/* Sending */
	struct sk_buff_head transmq;
	struct sk_buff_head backlogq;
	struct {
		u16 len;
		u16 limit;
		struct sk_buff *target_bskb;
	} backlog[5];
	u16 snd_nxt;
	u16 window;

	/* Reception */
	u16 rcv_nxt;
	u32 rcv_unacked;
	struct sk_buff_head deferdq;
	struct sk_buff_head *inputq;
	struct sk_buff_head *namedq;

	/* Congestion handling */
	struct sk_buff_head wakeupq;

	/* Fragmentation/reassembly */
	struct sk_buff *reasm_buf;
	struct sk_buff *reasm_tnlmsg;

	/* Broadcast */
	u16 ackers;
	u16 acked;
	struct tipc_link *bc_rcvlink;
	struct tipc_link *bc_sndlink;
	u8 nack_state;
	bool bc_peer_is_up;

	/* Statistics */
	struct tipc_stats stats;
};

/*
 * Error message prefixes
 */
static const char *link_co_err = "Link tunneling error, ";
static const char *link_rst_msg = "Resetting link ";

/* Send states for broadcast NACKs
 */
enum {
	BC_NACK_SND_CONDITIONAL,
	BC_NACK_SND_UNCONDITIONAL,
	BC_NACK_SND_SUPPRESS,
};

#define TIPC_BC_RETR_LIM  (jiffies + msecs_to_jiffies(10))
#define TIPC_UC_RETR_TIME (jiffies + msecs_to_jiffies(1))

/*
 * Interval between NACKs when packets arrive out of order
 */
#define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)

/* Link FSM states:
 */
enum {
	LINK_ESTABLISHED     = 0xe,
	LINK_ESTABLISHING    = 0xe  << 4,
	LINK_RESET           = 0x1  << 8,
	LINK_RESETTING       = 0x2  << 12,
	LINK_PEER_RESET      = 0xd  << 16,
	LINK_FAILINGOVER     = 0xf  << 20,
	LINK_SYNCHING        = 0xc  << 24
};

/* Link FSM state checking routines
 */
static int link_is_up(struct tipc_link *l)
{
	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
}

static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
			       struct sk_buff_head *xmitq);
static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
				      bool probe_reply, u16 rcvgap,
				      int tolerance, int priority,
				      struct sk_buff_head *xmitq);
static void link_print(struct tipc_link *l, const char *str);
static int tipc_link_build_nack_msg(struct tipc_link *l,
				    struct sk_buff_head *xmitq);
static void tipc_link_build_bc_init_msg(struct tipc_link *l,
					struct sk_buff_head *xmitq);
static bool tipc_link_release_pkts(struct tipc_link *l, u16 to);
static u16 tipc_build_gap_ack_blks(struct tipc_link *l, void *data);
static int tipc_link_advance_transmq(struct tipc_link *l, u16 acked, u16 gap,
				     struct tipc_gap_ack_blks *ga,
				     struct sk_buff_head *xmitq);

/*
 *  Simple non-static link routines (i.e. referenced outside this file)
 */
bool tipc_link_is_up(struct tipc_link *l)
{
	return link_is_up(l);
}

bool tipc_link_peer_is_down(struct tipc_link *l)
{
	return l->state == LINK_PEER_RESET;
}

bool tipc_link_is_reset(struct tipc_link *l)
{
	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
}

bool tipc_link_is_establishing(struct tipc_link *l)
{
	return l->state == LINK_ESTABLISHING;
}

bool tipc_link_is_synching(struct tipc_link *l)
{
	return l->state == LINK_SYNCHING;
}

bool tipc_link_is_failingover(struct tipc_link *l)
{
	return l->state == LINK_FAILINGOVER;
}

bool tipc_link_is_blocked(struct tipc_link *l)
{
	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
}

static bool link_is_bc_sndlink(struct tipc_link *l)
{
	return !l->bc_sndlink;
}

static bool link_is_bc_rcvlink(struct tipc_link *l)
{
	return ((l->bc_rcvlink == l) && !link_is_bc_sndlink(l));
}

void tipc_link_set_active(struct tipc_link *l, bool active)
{
	l->active = active;
}

u32 tipc_link_id(struct tipc_link *l)
{
	return l->peer_bearer_id << 16 | l->bearer_id;
}

int tipc_link_window(struct tipc_link *l)
{
	return l->window;
}

int tipc_link_prio(struct tipc_link *l)
{
	return l->priority;
}

unsigned long tipc_link_tolerance(struct tipc_link *l)
{
	return l->tolerance;
}

struct sk_buff_head *tipc_link_inputq(struct tipc_link *l)
{
	return l->inputq;
}

char tipc_link_plane(struct tipc_link *l)
{
	return l->net_plane;
}

void tipc_link_update_caps(struct tipc_link *l, u16 capabilities)
{
	l->peer_caps = capabilities;
}

void tipc_link_add_bc_peer(struct tipc_link *snd_l,
			   struct tipc_link *uc_l,
			   struct sk_buff_head *xmitq)
{
	struct tipc_link *rcv_l = uc_l->bc_rcvlink;

	snd_l->ackers++;
	rcv_l->acked = snd_l->snd_nxt - 1;
	snd_l->state = LINK_ESTABLISHED;
	tipc_link_build_bc_init_msg(uc_l, xmitq);
}

void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
			      struct tipc_link *rcv_l,
			      struct sk_buff_head *xmitq)
{
	u16 ack = snd_l->snd_nxt - 1;

	snd_l->ackers--;
	rcv_l->bc_peer_is_up = true;
	rcv_l->state = LINK_ESTABLISHED;
	tipc_link_bc_ack_rcv(rcv_l, ack, xmitq);
	trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
	tipc_link_reset(rcv_l);
	rcv_l->state = LINK_RESET;
	if (!snd_l->ackers) {
		trace_tipc_link_reset(snd_l, TIPC_DUMP_ALL, "zero ackers!");
		tipc_link_reset(snd_l);
		snd_l->state = LINK_RESET;
		__skb_queue_purge(xmitq);
	}
}

int tipc_link_bc_peers(struct tipc_link *l)
{
	return l->ackers;
}

static u16 link_bc_rcv_gap(struct tipc_link *l)
{
	struct sk_buff *skb = skb_peek(&l->deferdq);
	u16 gap = 0;

	if (more(l->snd_nxt, l->rcv_nxt))
		gap = l->snd_nxt - l->rcv_nxt;
	if (skb)
		gap = buf_seqno(skb) - l->rcv_nxt;
	return gap;
}

void tipc_link_set_mtu(struct tipc_link *l, int mtu)
{
	l->mtu = mtu;
}

int tipc_link_mtu(struct tipc_link *l)
{
	return l->mtu;
}

int tipc_link_mss(struct tipc_link *l)
{
#ifdef CONFIG_TIPC_CRYPTO
	return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
#else
	return l->mtu - INT_H_SIZE;
#endif
}

u16 tipc_link_rcv_nxt(struct tipc_link *l)
{
	return l->rcv_nxt;
}

u16 tipc_link_acked(struct tipc_link *l)
{
	return l->acked;
}

char *tipc_link_name(struct tipc_link *l)
{
	return l->name;
}

u32 tipc_link_state(struct tipc_link *l)
{
	return l->state;
}

/**
 * tipc_link_create - create a new link
 * @n: pointer to associated node
 * @if_name: associated interface name
 * @bearer_id: id (index) of associated bearer
 * @tolerance: link tolerance to be used by link
 * @net_plane: network plane (A,B,c..) this link belongs to
 * @mtu: mtu to be advertised by link
 * @priority: priority to be used by link
 * @window: send window to be used by link
 * @session: session to be used by link
 * @ownnode: identity of own node
 * @peer: node id of peer node
 * @peer_caps: bitmap describing peer node capabilities
 * @bc_sndlink: the namespace global link used for broadcast sending
 * @bc_rcvlink: the peer specific link used for broadcast reception
 * @inputq: queue to put messages ready for delivery
 * @namedq: queue to put binding table update messages ready for delivery
 * @link: return value, pointer to put the created link
 *
 * Returns true if link was created, otherwise false
 */
bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
		      int tolerance, char net_plane, u32 mtu, int priority,
		      int window, u32 session, u32 self,
		      u32 peer, u8 *peer_id, u16 peer_caps,
		      struct tipc_link *bc_sndlink,
		      struct tipc_link *bc_rcvlink,
		      struct sk_buff_head *inputq,
		      struct sk_buff_head *namedq,
		      struct tipc_link **link)
{
	char peer_str[NODE_ID_STR_LEN] = {0,};
	char self_str[NODE_ID_STR_LEN] = {0,};
	struct tipc_link *l;

	l = kzalloc(sizeof(*l), GFP_ATOMIC);
	if (!l)
		return false;
	*link = l;
	l->session = session;

	/* Set link name for unicast links only */
	if (peer_id) {
		tipc_nodeid2string(self_str, tipc_own_id(net));
		if (strlen(self_str) > 16)
			sprintf(self_str, "%x", self);
		tipc_nodeid2string(peer_str, peer_id);
		if (strlen(peer_str) > 16)
			sprintf(peer_str, "%x", peer);
	}
	/* Peer i/f name will be completed by reset/activate message */
	snprintf(l->name, sizeof(l->name), "%s:%s-%s:unknown",
		 self_str, if_name, peer_str);

	strcpy(l->if_name, if_name);
	l->addr = peer;
	l->peer_caps = peer_caps;
	l->net = net;
	l->in_session = false;
	l->bearer_id = bearer_id;
	l->tolerance = tolerance;
	if (bc_rcvlink)
		bc_rcvlink->tolerance = tolerance;
	l->net_plane = net_plane;
	l->advertised_mtu = mtu;
	l->mtu = mtu;
	l->priority = priority;
	tipc_link_set_queue_limits(l, window);
	l->ackers = 1;
	l->bc_sndlink = bc_sndlink;
	l->bc_rcvlink = bc_rcvlink;
	l->inputq = inputq;
	l->namedq = namedq;
	l->state = LINK_RESETTING;
	__skb_queue_head_init(&l->transmq);
	__skb_queue_head_init(&l->backlogq);
	__skb_queue_head_init(&l->deferdq);
	__skb_queue_head_init(&l->failover_deferdq);
	skb_queue_head_init(&l->wakeupq);
	skb_queue_head_init(l->inputq);
	return true;
}

/**
 * tipc_link_bc_create - create new link to be used for broadcast
 * @n: pointer to associated node
 * @mtu: mtu to be used initially if no peers
 * @window: send window to be used
 * @inputq: queue to put messages ready for delivery
 * @namedq: queue to put binding table update messages ready for delivery
 * @link: return value, pointer to put the created link
 *
 * Returns true if link was created, otherwise false
 */
bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
			 int mtu, int window, u16 peer_caps,
			 struct sk_buff_head *inputq,
			 struct sk_buff_head *namedq,
			 struct tipc_link *bc_sndlink,
			 struct tipc_link **link)
{
	struct tipc_link *l;

	if (!tipc_link_create(net, "", MAX_BEARERS, 0, 'Z', mtu, 0, window,
			      0, ownnode, peer, NULL, peer_caps, bc_sndlink,
			      NULL, inputq, namedq, link))
		return false;

	l = *link;
	strcpy(l->name, tipc_bclink_name);
	trace_tipc_link_reset(l, TIPC_DUMP_ALL, "bclink created!");
	tipc_link_reset(l);
	l->state = LINK_RESET;
	l->ackers = 0;
	l->bc_rcvlink = l;

	/* Broadcast send link is always up */
	if (link_is_bc_sndlink(l))
		l->state = LINK_ESTABLISHED;

	/* Disable replicast if even a single peer doesn't support it */
	if (link_is_bc_rcvlink(l) && !(peer_caps & TIPC_BCAST_RCAST))
		tipc_bcast_disable_rcast(net);

	return true;
}

/**
 * tipc_link_fsm_evt - link finite state machine
 * @l: pointer to link
 * @evt: state machine event to be processed
 */
int tipc_link_fsm_evt(struct tipc_link *l, int evt)
{
	int rc = 0;
	int old_state = l->state;

	switch (l->state) {
	case LINK_RESETTING:
		switch (evt) {
		case LINK_PEER_RESET_EVT:
			l->state = LINK_PEER_RESET;
			break;
		case LINK_RESET_EVT:
			l->state = LINK_RESET;
			break;
		case LINK_FAILURE_EVT:
		case LINK_FAILOVER_BEGIN_EVT:
		case LINK_ESTABLISH_EVT:
		case LINK_FAILOVER_END_EVT:
		case LINK_SYNCH_BEGIN_EVT:
		case LINK_SYNCH_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case LINK_RESET:
		switch (evt) {
		case LINK_PEER_RESET_EVT:
			l->state = LINK_ESTABLISHING;
			break;
		case LINK_FAILOVER_BEGIN_EVT:
			l->state = LINK_FAILINGOVER;
		case LINK_FAILURE_EVT:
		case LINK_RESET_EVT:
		case LINK_ESTABLISH_EVT:
		case LINK_FAILOVER_END_EVT:
			break;
		case LINK_SYNCH_BEGIN_EVT:
		case LINK_SYNCH_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case LINK_PEER_RESET:
		switch (evt) {
		case LINK_RESET_EVT:
			l->state = LINK_ESTABLISHING;
			break;
		case LINK_PEER_RESET_EVT:
		case LINK_ESTABLISH_EVT:
		case LINK_FAILURE_EVT:
			break;
		case LINK_SYNCH_BEGIN_EVT:
		case LINK_SYNCH_END_EVT:
		case LINK_FAILOVER_BEGIN_EVT:
		case LINK_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case LINK_FAILINGOVER:
		switch (evt) {
		case LINK_FAILOVER_END_EVT:
			l->state = LINK_RESET;
			break;
		case LINK_PEER_RESET_EVT:
		case LINK_RESET_EVT:
		case LINK_ESTABLISH_EVT:
		case LINK_FAILURE_EVT:
			break;
		case LINK_FAILOVER_BEGIN_EVT:
		case LINK_SYNCH_BEGIN_EVT:
		case LINK_SYNCH_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case LINK_ESTABLISHING:
		switch (evt) {
		case LINK_ESTABLISH_EVT:
			l->state = LINK_ESTABLISHED;
			break;
		case LINK_FAILOVER_BEGIN_EVT:
			l->state = LINK_FAILINGOVER;
			break;
		case LINK_RESET_EVT:
			l->state = LINK_RESET;
			break;
		case LINK_FAILURE_EVT:
		case LINK_PEER_RESET_EVT:
		case LINK_SYNCH_BEGIN_EVT:
		case LINK_FAILOVER_END_EVT:
			break;
		case LINK_SYNCH_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case LINK_ESTABLISHED:
		switch (evt) {
		case LINK_PEER_RESET_EVT:
			l->state = LINK_PEER_RESET;
			rc |= TIPC_LINK_DOWN_EVT;
			break;
		case LINK_FAILURE_EVT:
			l->state = LINK_RESETTING;
			rc |= TIPC_LINK_DOWN_EVT;
			break;
		case LINK_RESET_EVT:
			l->state = LINK_RESET;
			break;
		case LINK_ESTABLISH_EVT:
		case LINK_SYNCH_END_EVT:
			break;
		case LINK_SYNCH_BEGIN_EVT:
			l->state = LINK_SYNCHING;
			break;
		case LINK_FAILOVER_BEGIN_EVT:
		case LINK_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	case LINK_SYNCHING:
		switch (evt) {
		case LINK_PEER_RESET_EVT:
			l->state = LINK_PEER_RESET;
			rc |= TIPC_LINK_DOWN_EVT;
			break;
		case LINK_FAILURE_EVT:
			l->state = LINK_RESETTING;
			rc |= TIPC_LINK_DOWN_EVT;
			break;
		case LINK_RESET_EVT:
			l->state = LINK_RESET;
			break;
		case LINK_ESTABLISH_EVT:
		case LINK_SYNCH_BEGIN_EVT:
			break;
		case LINK_SYNCH_END_EVT:
			l->state = LINK_ESTABLISHED;
			break;
		case LINK_FAILOVER_BEGIN_EVT:
		case LINK_FAILOVER_END_EVT:
		default:
			goto illegal_evt;
		}
		break;
	default:
		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
	}
	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
	return rc;
illegal_evt:
	pr_err("Illegal FSM event %x in state %x on link %s\n",
	       evt, l->state, l->name);
	trace_tipc_link_fsm(l->name, old_state, l->state, evt);
	return rc;
}

/* link_profile_stats - update statistical profiling of traffic
 */
static void link_profile_stats(struct tipc_link *l)
{
	struct sk_buff *skb;
	struct tipc_msg *msg;
	int length;

	/* Update counters used in statistical profiling of send traffic */
	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
	l->stats.queue_sz_counts++;

	skb = skb_peek(&l->transmq);
	if (!skb)
		return;
	msg = buf_msg(skb);
	length = msg_size(msg);

	if (msg_user(msg) == MSG_FRAGMENTER) {
		if (msg_type(msg) != FIRST_FRAGMENT)
			return;
		length = msg_size(msg_inner_hdr(msg));
	}
	l->stats.msg_lengths_total += length;
	l->stats.msg_length_counts++;
	if (length <= 64)
		l->stats.msg_length_profile[0]++;
	else if (length <= 256)
		l->stats.msg_length_profile[1]++;
	else if (length <= 1024)
		l->stats.msg_length_profile[2]++;
	else if (length <= 4096)
		l->stats.msg_length_profile[3]++;
	else if (length <= 16384)
		l->stats.msg_length_profile[4]++;
	else if (length <= 32768)
		l->stats.msg_length_profile[5]++;
	else
		l->stats.msg_length_profile[6]++;
}

/**
 * tipc_link_too_silent - check if link is "too silent"
 * @l: tipc link to be checked
 *
 * Returns true if the link 'silent_intv_cnt' is about to reach the
 * 'abort_limit' value, otherwise false
 */
bool tipc_link_too_silent(struct tipc_link *l)
{
	return (l->silent_intv_cnt + 2 > l->abort_limit);
}

/* tipc_link_timeout - perform periodic task as instructed from node timeout
 */
int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
{
	int mtyp = 0;
	int rc = 0;
	bool state = false;
	bool probe = false;
	bool setup = false;
	u16 bc_snt = l->bc_sndlink->snd_nxt - 1;
	u16 bc_acked = l->bc_rcvlink->acked;
	struct tipc_mon_state *mstate = &l->mon_state;

	trace_tipc_link_timeout(l, TIPC_DUMP_NONE, " ");
	trace_tipc_link_too_silent(l, TIPC_DUMP_ALL, " ");
	switch (l->state) {
	case LINK_ESTABLISHED:
	case LINK_SYNCHING:
		mtyp = STATE_MSG;
		link_profile_stats(l);
		tipc_mon_get_state(l->net, l->addr, mstate, l->bearer_id);
		if (mstate->reset || (l->silent_intv_cnt > l->abort_limit))
			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
		state = bc_acked != bc_snt;
		state |= l->bc_rcvlink->rcv_unacked;
		state |= l->rcv_unacked;
		state |= !skb_queue_empty(&l->transmq);
		state |= !skb_queue_empty(&l->deferdq);
		probe = mstate->probing;
		probe |= l->silent_intv_cnt;
		if (probe || mstate->monitoring)
			l->silent_intv_cnt++;
		break;
	case LINK_RESET:
		setup = l->rst_cnt++ <= 4;
		setup |= !(l->rst_cnt % 16);
		mtyp = RESET_MSG;
		break;
	case LINK_ESTABLISHING:
		setup = true;
		mtyp = ACTIVATE_MSG;
		break;
	case LINK_PEER_RESET:
	case LINK_RESETTING:
	case LINK_FAILINGOVER:
		break;
	default:
		break;
	}

	if (state || probe || setup)
		tipc_link_build_proto_msg(l, mtyp, probe, 0, 0, 0, 0, xmitq);

	return rc;
}

/**
 * link_schedule_user - schedule a message sender for wakeup after congestion
 * @l: congested link
 * @hdr: header of message that is being sent
 * Create pseudo msg to send back to user when congestion abates
 */
static int link_schedule_user(struct tipc_link *l, struct tipc_msg *hdr)
{
	u32 dnode = tipc_own_addr(l->net);
	u32 dport = msg_origport(hdr);
	struct sk_buff *skb;

	/* Create and schedule wakeup pseudo message */
	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
			      dnode, l->addr, dport, 0, 0);
	if (!skb)
		return -ENOBUFS;
	msg_set_dest_droppable(buf_msg(skb), true);
	TIPC_SKB_CB(skb)->chain_imp = msg_importance(hdr);
	skb_queue_tail(&l->wakeupq, skb);
	l->stats.link_congs++;
	trace_tipc_link_conges(l, TIPC_DUMP_ALL, "wakeup scheduled!");
	return -ELINKCONG;
}

/**
 * link_prepare_wakeup - prepare users for wakeup after congestion
 * @l: congested link
 * Wake up a number of waiting users, as permitted by available space
 * in the send queue
 */
static void link_prepare_wakeup(struct tipc_link *l)
{
	struct sk_buff_head *wakeupq = &l->wakeupq;
	struct sk_buff_head *inputq = l->inputq;
	struct sk_buff *skb, *tmp;
	struct sk_buff_head tmpq;
	int avail[5] = {0,};
	int imp = 0;

	__skb_queue_head_init(&tmpq);

	for (; imp <= TIPC_SYSTEM_IMPORTANCE; imp++)
		avail[imp] = l->backlog[imp].limit - l->backlog[imp].len;

	skb_queue_walk_safe(wakeupq, skb, tmp) {
		imp = TIPC_SKB_CB(skb)->chain_imp;
		if (avail[imp] <= 0)
			continue;
		avail[imp]--;
		__skb_unlink(skb, wakeupq);
		__skb_queue_tail(&tmpq, skb);
	}

	spin_lock_bh(&inputq->lock);
	skb_queue_splice_tail(&tmpq, inputq);
	spin_unlock_bh(&inputq->lock);

}

void tipc_link_reset(struct tipc_link *l)
{
	struct sk_buff_head list;
	u32 imp;

	__skb_queue_head_init(&list);

	l->in_session = false;
	/* Force re-synch of peer session number before establishing */
	l->peer_session--;
	l->session++;
	l->mtu = l->advertised_mtu;

	spin_lock_bh(&l->wakeupq.lock);
	skb_queue_splice_init(&l->wakeupq, &list);
	spin_unlock_bh(&l->wakeupq.lock);

	spin_lock_bh(&l->inputq->lock);
	skb_queue_splice_init(&list, l->inputq);
	spin_unlock_bh(&l->inputq->lock);

	__skb_queue_purge(&l->transmq);
	__skb_queue_purge(&l->deferdq);
	__skb_queue_purge(&l->backlogq);
	__skb_queue_purge(&l->failover_deferdq);
	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
		l->backlog[imp].len = 0;
		l->backlog[imp].target_bskb = NULL;
	}
	kfree_skb(l->reasm_buf);
	kfree_skb(l->reasm_tnlmsg);
	kfree_skb(l->failover_reasm_skb);
	l->reasm_buf = NULL;
	l->reasm_tnlmsg = NULL;
	l->failover_reasm_skb = NULL;
	l->rcv_unacked = 0;
	l->snd_nxt = 1;
	l->rcv_nxt = 1;
	l->snd_nxt_state = 1;
	l->rcv_nxt_state = 1;
	l->acked = 0;
	l->silent_intv_cnt = 0;
	l->rst_cnt = 0;
	l->bc_peer_is_up = false;
	memset(&l->mon_state, 0, sizeof(l->mon_state));
	tipc_link_reset_stats(l);
}

/**
 * tipc_link_xmit(): enqueue buffer list according to queue situation
 * @link: link to use
 * @list: chain of buffers containing message
 * @xmitq: returned list of packets to be sent by caller
 *
 * Consumes the buffer chain.
 * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
 * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
 */
int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
		   struct sk_buff_head *xmitq)
{
	struct tipc_msg *hdr = buf_msg(skb_peek(list));
	struct sk_buff_head *backlogq = &l->backlogq;
	struct sk_buff_head *transmq = &l->transmq;
	struct sk_buff *skb, *_skb;
	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
	u16 ack = l->rcv_nxt - 1;
	u16 seqno = l->snd_nxt;
	int pkt_cnt = skb_queue_len(list);
	int imp = msg_importance(hdr);
	unsigned int mss = tipc_link_mss(l);
	unsigned int maxwin = l->window;
	unsigned int mtu = l->mtu;
	bool new_bundle;
	int rc = 0;

	if (unlikely(msg_size(hdr) > mtu)) {
		pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n",
			skb_queue_len(list), msg_user(hdr),
			msg_type(hdr), msg_size(hdr), mtu);
		__skb_queue_purge(list);
		return -EMSGSIZE;
	}

	/* Allow oversubscription of one data msg per source at congestion */
	if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
		if (imp == TIPC_SYSTEM_IMPORTANCE) {
			pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
			return -ENOBUFS;
		}
		rc = link_schedule_user(l, hdr);
	}

	if (pkt_cnt > 1) {
		l->stats.sent_fragmented++;
		l->stats.sent_fragments += pkt_cnt;
	}

	/* Prepare each packet for sending, and add to relevant queue: */
	while ((skb = __skb_dequeue(list))) {
		if (likely(skb_queue_len(transmq) < maxwin)) {
			hdr = buf_msg(skb);
			msg_set_seqno(hdr, seqno);
			msg_set_ack(hdr, ack);
			msg_set_bcast_ack(hdr, bc_ack);
			_skb = skb_clone(skb, GFP_ATOMIC);
			if (!_skb) {
				kfree_skb(skb);
				__skb_queue_purge(list);
				return -ENOBUFS;
			}
			__skb_queue_tail(transmq, skb);
			/* next retransmit attempt */
			if (link_is_bc_sndlink(l))
				TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
			__skb_queue_tail(xmitq, _skb);
			TIPC_SKB_CB(skb)->ackers = l->ackers;
			l->rcv_unacked = 0;
			l->stats.sent_pkts++;
			seqno++;
			continue;
		}
		if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
					mss, l->addr, &new_bundle)) {
			if (skb) {
				/* Keep a ref. to the skb for next try */
				l->backlog[imp].target_bskb = skb;
				l->backlog[imp].len++;
				__skb_queue_tail(backlogq, skb);
			} else {
				if (new_bundle) {
					l->stats.sent_bundles++;
					l->stats.sent_bundled++;
				}
				l->stats.sent_bundled++;
			}
			continue;
		}
		l->backlog[imp].target_bskb = NULL;
		l->backlog[imp].len += (1 + skb_queue_len(list));
		__skb_queue_tail(backlogq, skb);
		skb_queue_splice_tail_init(list, backlogq);
	}
	l->snd_nxt = seqno;
	return rc;
}

static void tipc_link_advance_backlog(struct tipc_link *l,
				      struct sk_buff_head *xmitq)
{
	struct sk_buff *skb, *_skb;
	struct tipc_msg *hdr;
	u16 seqno = l->snd_nxt;
	u16 ack = l->rcv_nxt - 1;
	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
	u32 imp;

	while (skb_queue_len(&l->transmq) < l->window) {
		skb = skb_peek(&l->backlogq);
		if (!skb)
			break;
		_skb = skb_clone(skb, GFP_ATOMIC);
		if (!_skb)
			break;
		__skb_dequeue(&l->backlogq);
		hdr = buf_msg(skb);
		imp = msg_importance(hdr);
		l->backlog[imp].len--;
		if (unlikely(skb == l->backlog[imp].target_bskb))
			l->backlog[imp].target_bskb = NULL;
		__skb_queue_tail(&l->transmq, skb);
		/* next retransmit attempt */
		if (link_is_bc_sndlink(l))
			TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;

		__skb_queue_tail(xmitq, _skb);
		TIPC_SKB_CB(skb)->ackers = l->ackers;
		msg_set_seqno(hdr, seqno);
		msg_set_ack(hdr, ack);
		msg_set_bcast_ack(hdr, bc_ack);
		l->rcv_unacked = 0;
		l->stats.sent_pkts++;
		seqno++;
	}
	l->snd_nxt = seqno;
}

/**
 * link_retransmit_failure() - Detect repeated retransmit failures
 * @l: tipc link sender
 * @r: tipc link receiver (= l in case of unicast)
 * @rc: returned code
 *
 * Return: true if the repeated retransmit failures happens, otherwise
 * false
 */
static bool link_retransmit_failure(struct tipc_link *l, struct tipc_link *r,
				    int *rc)
{
	struct sk_buff *skb = skb_peek(&l->transmq);
	struct tipc_msg *hdr;

	if (!skb)
		return false;

	if (!TIPC_SKB_CB(skb)->retr_cnt)
		return false;

	if (!time_after(jiffies, TIPC_SKB_CB(skb)->retr_stamp +
			msecs_to_jiffies(r->tolerance * 10)))
		return false;

	hdr = buf_msg(skb);
	if (link_is_bc_sndlink(l) && !less(r->acked, msg_seqno(hdr)))
		return false;

	pr_warn("Retransmission failure on link <%s>\n", l->name);
	link_print(l, "State of link ");
	pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
		msg_user(hdr), msg_type(hdr), msg_size(hdr), msg_errcode(hdr));
	pr_info("sqno %u, prev: %x, dest: %x\n",
		msg_seqno(hdr), msg_prevnode(hdr), msg_destnode(hdr));
	pr_info("retr_stamp %d, retr_cnt %d\n",
		jiffies_to_msecs(TIPC_SKB_CB(skb)->retr_stamp),
		TIPC_SKB_CB(skb)->retr_cnt);

	trace_tipc_list_dump(&l->transmq, true, "retrans failure!");
	trace_tipc_link_dump(l, TIPC_DUMP_NONE, "retrans failure!");
	trace_tipc_link_dump(r, TIPC_DUMP_NONE, "retrans failure!");

	if (link_is_bc_sndlink(l)) {
		r->state = LINK_RESET;
		*rc = TIPC_LINK_DOWN_EVT;
	} else {
		*rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
	}

	return true;
}

/* tipc_link_bc_retrans() - retransmit zero or more packets
 * @l: the link to transmit on
 * @r: the receiving link ordering the retransmit. Same as l if unicast
 * @from: retransmit from (inclusive) this sequence number
 * @to: retransmit to (inclusive) this sequence number
 * xmitq: queue for accumulating the retransmitted packets
 */
static int tipc_link_bc_retrans(struct tipc_link *l, struct tipc_link *r,
				u16 from, u16 to, struct sk_buff_head *xmitq)
{
	struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
	u16 ack = l->rcv_nxt - 1;
	struct tipc_msg *hdr;
	int rc = 0;

	if (!skb)
		return 0;
	if (less(to, from))
		return 0;

	trace_tipc_link_retrans(r, from, to, &l->transmq);

	if (link_retransmit_failure(l, r, &rc))
		return rc;

	skb_queue_walk(&l->transmq, skb) {
		hdr = buf_msg(skb);
		if (less(msg_seqno(hdr), from))
			continue;
		if (more(msg_seqno(hdr), to))
			break;

		if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
			continue;
		TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
		_skb = pskb_copy(skb, GFP_ATOMIC);
		if (!_skb)
			return 0;
		hdr = buf_msg(_skb);
		msg_set_ack(hdr, ack);
		msg_set_bcast_ack(hdr, bc_ack);
		_skb->priority = TC_PRIO_CONTROL;
		__skb_queue_tail(xmitq, _skb);
		l->stats.retransmitted++;

		/* Increase actual retrans counter & mark first time */
		if (!TIPC_SKB_CB(skb)->retr_cnt++)
			TIPC_SKB_CB(skb)->retr_stamp = jiffies;
	}
	return 0;
}

/* tipc_data_input - deliver data and name distr msgs to upper layer
 *
 * Consumes buffer if message is of right type
 * Node lock must be held
 */
static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
			    struct sk_buff_head *inputq)
{
	struct sk_buff_head *mc_inputq = l->bc_rcvlink->inputq;
	struct tipc_msg *hdr = buf_msg(skb);

	switch (msg_user(hdr)) {
	case TIPC_LOW_IMPORTANCE:
	case TIPC_MEDIUM_IMPORTANCE:
	case TIPC_HIGH_IMPORTANCE:
	case TIPC_CRITICAL_IMPORTANCE:
		if (unlikely(msg_in_group(hdr) || msg_mcast(hdr))) {
			skb_queue_tail(mc_inputq, skb);
			return true;
		}
		/* fall through */
	case CONN_MANAGER:
		skb_queue_tail(inputq, skb);
		return true;
	case GROUP_PROTOCOL:
		skb_queue_tail(mc_inputq, skb);
		return true;
	case NAME_DISTRIBUTOR:
		l->bc_rcvlink->state = LINK_ESTABLISHED;
		skb_queue_tail(l->namedq, skb);
		return true;
	case MSG_BUNDLER:
	case TUNNEL_PROTOCOL:
	case MSG_FRAGMENTER:
	case BCAST_PROTOCOL:
		return false;
	default:
		pr_warn("Dropping received illegal msg type\n");
		kfree_skb(skb);
		return true;
	};
}

/* tipc_link_input - process packet that has passed link protocol check
 *
 * Consumes buffer
 */
static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
			   struct sk_buff_head *inputq,
			   struct sk_buff **reasm_skb)
{
	struct tipc_msg *hdr = buf_msg(skb);
	struct sk_buff *iskb;
	struct sk_buff_head tmpq;
	int usr = msg_user(hdr);
	int pos = 0;

	if (usr == MSG_BUNDLER) {
		skb_queue_head_init(&tmpq);
		l->stats.recv_bundles++;
		l->stats.recv_bundled += msg_msgcnt(hdr);
		while (tipc_msg_extract(skb, &iskb, &pos))
			tipc_data_input(l, iskb, &tmpq);
		tipc_skb_queue_splice_tail(&tmpq, inputq);
		return 0;
	} else if (usr == MSG_FRAGMENTER) {
		l->stats.recv_fragments++;
		if (tipc_buf_append(reasm_skb, &skb)) {
			l->stats.recv_fragmented++;
			tipc_data_input(l, skb, inputq);
		} else if (!*reasm_skb && !link_is_bc_rcvlink(l)) {
			pr_warn_ratelimited("Unable to build fragment list\n");
			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
		}
		return 0;
	} else if (usr == BCAST_PROTOCOL) {
		tipc_bcast_lock(l->net);
		tipc_link_bc_init_rcv(l->bc_rcvlink, hdr);
		tipc_bcast_unlock(l->net);
	}

	kfree_skb(skb);
	return 0;
}

/* tipc_link_tnl_rcv() - receive TUNNEL_PROTOCOL message, drop or process the
 *			 inner message along with the ones in the old link's
 *			 deferdq
 * @l: tunnel link
 * @skb: TUNNEL_PROTOCOL message
 * @inputq: queue to put messages ready for delivery
 */
static int tipc_link_tnl_rcv(struct tipc_link *l, struct sk_buff *skb,
			     struct sk_buff_head *inputq)
{
	struct sk_buff **reasm_skb = &l->failover_reasm_skb;
	struct sk_buff **reasm_tnlmsg = &l->reasm_tnlmsg;
	struct sk_buff_head *fdefq = &l->failover_deferdq;
	struct tipc_msg *hdr = buf_msg(skb);
	struct sk_buff *iskb;
	int ipos = 0;
	int rc = 0;
	u16 seqno;

	if (msg_type(hdr) == SYNCH_MSG) {
		kfree_skb(skb);
		return 0;
	}

	/* Not a fragment? */
	if (likely(!msg_nof_fragms(hdr))) {
		if (unlikely(!tipc_msg_extract(skb, &iskb, &ipos))) {
			pr_warn_ratelimited("Unable to extract msg, defq: %d\n",
					    skb_queue_len(fdefq));
			return 0;
		}
		kfree_skb(skb);
	} else {
		/* Set fragment type for buf_append */
		if (msg_fragm_no(hdr) == 1)
			msg_set_type(hdr, FIRST_FRAGMENT);
		else if (msg_fragm_no(hdr) < msg_nof_fragms(hdr))
			msg_set_type(hdr, FRAGMENT);
		else
			msg_set_type(hdr, LAST_FRAGMENT);

		if (!tipc_buf_append(reasm_tnlmsg, &skb)) {
			/* Successful but non-complete reassembly? */
			if (*reasm_tnlmsg || link_is_bc_rcvlink(l))
				return 0;
			pr_warn_ratelimited("Unable to reassemble tunnel msg\n");
			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
		}
		iskb = skb;
	}

	do {
		seqno = buf_seqno(iskb);
		if (unlikely(less(seqno, l->drop_point))) {
			kfree_skb(iskb);
			continue;
		}
		if (unlikely(seqno != l->drop_point)) {
			__tipc_skb_queue_sorted(fdefq, seqno, iskb);
			continue;
		}

		l->drop_point++;
		if (!tipc_data_input(l, iskb, inputq))
			rc |= tipc_link_input(l, iskb, inputq, reasm_skb);
		if (unlikely(rc))
			break;
	} while ((iskb = __tipc_skb_dequeue(fdefq, l->drop_point)));

	return rc;
}

static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
{
	bool released = false;
	struct sk_buff *skb, *tmp;

	skb_queue_walk_safe(&l->transmq, skb, tmp) {
		if (more(buf_seqno(skb), acked))
			break;
		__skb_unlink(skb, &l->transmq);
		kfree_skb(skb);
		released = true;
	}
	return released;
}

/* tipc_build_gap_ack_blks - build Gap ACK blocks
 * @l: tipc link that data have come with gaps in sequence if any
 * @data: data buffer to store the Gap ACK blocks after built
 *
 * returns the actual allocated memory size
 */
static u16 tipc_build_gap_ack_blks(struct tipc_link *l, void *data)
{
	struct sk_buff *skb = skb_peek(&l->deferdq);
	struct tipc_gap_ack_blks *ga = data;
	u16 len, expect, seqno = 0;
	u8 n = 0;

	if (!skb)
		goto exit;

	expect = buf_seqno(skb);
	skb_queue_walk(&l->deferdq, skb) {
		seqno = buf_seqno(skb);
		if (unlikely(more(seqno, expect))) {
			ga->gacks[n].ack = htons(expect - 1);
			ga->gacks[n].gap = htons(seqno - expect);
			if (++n >= MAX_GAP_ACK_BLKS) {
				pr_info_ratelimited("Too few Gap ACK blocks!\n");
				goto exit;
			}
		} else if (unlikely(less(seqno, expect))) {
			pr_warn("Unexpected skb in deferdq!\n");
			continue;
		}
		expect = seqno + 1;
	}

	/* last block */
	ga->gacks[n].ack = htons(seqno);
	ga->gacks[n].gap = 0;
	n++;

exit:
	len = tipc_gap_ack_blks_sz(n);
	ga->len = htons(len);
	ga->gack_cnt = n;
	return len;
}

/* tipc_link_advance_transmq - advance TIPC link transmq queue by releasing
 *			       acked packets, also doing retransmissions if
 *			       gaps found
 * @l: tipc link with transmq queue to be advanced
 * @acked: seqno of last packet acked by peer without any gaps before
 * @gap: # of gap packets
 * @ga: buffer pointer to Gap ACK blocks from peer
 * @xmitq: queue for accumulating the retransmitted packets if any
 *
 * In case of a repeated retransmit failures, the call will return shortly
 * with a returned code (e.g. TIPC_LINK_DOWN_EVT)
 */
static int tipc_link_advance_transmq(struct tipc_link *l, u16 acked, u16 gap,
				     struct tipc_gap_ack_blks *ga,
				     struct sk_buff_head *xmitq)
{
	struct sk_buff *skb, *_skb, *tmp;
	struct tipc_msg *hdr;
	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
	u16 ack = l->rcv_nxt - 1;
	bool passed = false;
	u16 seqno, n = 0;
	int rc = 0;

	skb_queue_walk_safe(&l->transmq, skb, tmp) {
		seqno = buf_seqno(skb);

next_gap_ack:
		if (less_eq(seqno, acked)) {
			/* release skb */
			__skb_unlink(skb, &l->transmq);
			kfree_skb(skb);
		} else if (less_eq(seqno, acked + gap)) {
			/* First, check if repeated retrans failures occurs? */
			if (!passed && link_retransmit_failure(l, l, &rc))
				return rc;
			passed = true;

			/* retransmit skb if unrestricted*/
			if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
				continue;
			TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
			_skb = pskb_copy(skb, GFP_ATOMIC);
			if (!_skb)
				continue;
			hdr = buf_msg(_skb);
			msg_set_ack(hdr, ack);
			msg_set_bcast_ack(hdr, bc_ack);
			_skb->priority = TC_PRIO_CONTROL;
			__skb_queue_tail(xmitq, _skb);
			l->stats.retransmitted++;

			/* Increase actual retrans counter & mark first time */
			if (!TIPC_SKB_CB(skb)->retr_cnt++)
				TIPC_SKB_CB(skb)->retr_stamp = jiffies;
		} else {
			/* retry with Gap ACK blocks if any */
			if (!ga || n >= ga->gack_cnt)
				break;
			acked = ntohs(ga->gacks[n].ack);
			gap = ntohs(ga->gacks[n].gap);
			n++;
			goto next_gap_ack;
		}
	}

	return 0;
}

/* tipc_link_build_state_msg: prepare link state message for transmission
 *
 * Note that sending of broadcast ack is coordinated among nodes, to reduce
 * risk of ack storms towards the sender
 */
int tipc_link_build_state_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
{
	if (!l)
		return 0;

	/* Broadcast ACK must be sent via a unicast link => defer to caller */
	if (link_is_bc_rcvlink(l)) {
		if (((l->rcv_nxt ^ tipc_own_addr(l->net)) & 0xf) != 0xf)
			return 0;
		l->rcv_unacked = 0;

		/* Use snd_nxt to store peer's snd_nxt in broadcast rcv link */
		l->snd_nxt = l->rcv_nxt;
		return TIPC_LINK_SND_STATE;
	}

	/* Unicast ACK */
	l->rcv_unacked = 0;
	l->stats.sent_acks++;
	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
	return 0;
}

/* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
 */
void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
{
	int mtyp = RESET_MSG;
	struct sk_buff *skb;

	if (l->state == LINK_ESTABLISHING)
		mtyp = ACTIVATE_MSG;

	tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, 0, xmitq);

	/* Inform peer that this endpoint is going down if applicable */
	skb = skb_peek_tail(xmitq);
	if (skb && (l->state == LINK_RESET))
		msg_set_peer_stopping(buf_msg(skb), 1);
}

/* tipc_link_build_nack_msg: prepare link nack message for transmission
 * Note that sending of broadcast NACK is coordinated among nodes, to
 * reduce the risk of NACK storms towards the sender
 */
static int tipc_link_build_nack_msg(struct tipc_link *l,
				    struct sk_buff_head *xmitq)
{
	u32 def_cnt = ++l->stats.deferred_recv;
	u32 defq_len = skb_queue_len(&l->deferdq);
	int match1, match2;

	if (link_is_bc_rcvlink(l)) {
		match1 = def_cnt & 0xf;
		match2 = tipc_own_addr(l->net) & 0xf;
		if (match1 == match2)
			return TIPC_LINK_SND_STATE;
		return 0;
	}

	if (defq_len >= 3 && !((defq_len - 3) % 16))
		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, 0, xmitq);
	return 0;
}

/* tipc_link_rcv - process TIPC packets/messages arriving from off-node
 * @l: the link that should handle the message
 * @skb: TIPC packet
 * @xmitq: queue to place packets to be sent after this call
 */
int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
		  struct sk_buff_head *xmitq)
{
	struct sk_buff_head *defq = &l->deferdq;
	struct tipc_msg *hdr = buf_msg(skb);
	u16 seqno, rcv_nxt, win_lim;
	int rc = 0;

	/* Verify and update link state */
	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
		return tipc_link_proto_rcv(l, skb, xmitq);

	/* Don't send probe at next timeout expiration */
	l->silent_intv_cnt = 0;

	do {
		hdr = buf_msg(skb);
		seqno = msg_seqno(hdr);
		rcv_nxt = l->rcv_nxt;
		win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;

		if (unlikely(!link_is_up(l))) {
			if (l->state == LINK_ESTABLISHING)
				rc = TIPC_LINK_UP_EVT;
			goto drop;
		}

		/* Drop if outside receive window */
		if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
			l->stats.duplicates++;
			goto drop;
		}

		/* Forward queues and wake up waiting users */
		if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
			tipc_link_advance_backlog(l, xmitq);
			if (unlikely(!skb_queue_empty(&l->wakeupq)))
				link_prepare_wakeup(l);
		}

		/* Defer delivery if sequence gap */
		if (unlikely(seqno != rcv_nxt)) {
			__tipc_skb_queue_sorted(defq, seqno, skb);
			rc |= tipc_link_build_nack_msg(l, xmitq);
			break;
		}

		/* Deliver packet */
		l->rcv_nxt++;
		l->stats.recv_pkts++;

		if (unlikely(msg_user(hdr) == TUNNEL_PROTOCOL))
			rc |= tipc_link_tnl_rcv(l, skb, l->inputq);
		else if (!tipc_data_input(l, skb, l->inputq))
			rc |= tipc_link_input(l, skb, l->inputq, &l->reasm_buf);
		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
			rc |= tipc_link_build_state_msg(l, xmitq);
		if (unlikely(rc & ~TIPC_LINK_SND_STATE))
			break;
	} while ((skb = __tipc_skb_dequeue(defq, l->rcv_nxt)));

	return rc;
drop:
	kfree_skb(skb);
	return rc;
}

static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
				      bool probe_reply, u16 rcvgap,
				      int tolerance, int priority,
				      struct sk_buff_head *xmitq)
{
	struct tipc_link *bcl = l->bc_rcvlink;
	struct sk_buff *skb;
	struct tipc_msg *hdr;
	struct sk_buff_head *dfq = &l->deferdq;
	bool node_up = link_is_up(bcl);
	struct tipc_mon_state *mstate = &l->mon_state;
	int dlen = 0;
	void *data;
	u16 glen = 0;

	/* Don't send protocol message during reset or link failover */
	if (tipc_link_is_blocked(l))
		return;

	if (!tipc_link_is_up(l) && (mtyp == STATE_MSG))
		return;

	if (!skb_queue_empty(dfq))
		rcvgap = buf_seqno(skb_peek(dfq)) - l->rcv_nxt;

	skb = tipc_msg_create(LINK_PROTOCOL, mtyp, INT_H_SIZE,
			      tipc_max_domain_size + MAX_GAP_ACK_BLKS_SZ,
			      l->addr, tipc_own_addr(l->net), 0, 0, 0);
	if (!skb)
		return;

	hdr = buf_msg(skb);
	data = msg_data(hdr);
	msg_set_session(hdr, l->session);
	msg_set_bearer_id(hdr, l->bearer_id);
	msg_set_net_plane(hdr, l->net_plane);
	msg_set_next_sent(hdr, l->snd_nxt);
	msg_set_ack(hdr, l->rcv_nxt - 1);
	msg_set_bcast_ack(hdr, bcl->rcv_nxt - 1);
	msg_set_bc_ack_invalid(hdr, !node_up);
	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
	msg_set_link_tolerance(hdr, tolerance);
	msg_set_linkprio(hdr, priority);
	msg_set_redundant_link(hdr, node_up);
	msg_set_seq_gap(hdr, 0);
	msg_set_seqno(hdr, l->snd_nxt + U16_MAX / 2);

	if (mtyp == STATE_MSG) {
		if (l->peer_caps & TIPC_LINK_PROTO_SEQNO)
			msg_set_seqno(hdr, l->snd_nxt_state++);
		msg_set_seq_gap(hdr, rcvgap);
		msg_set_bc_gap(hdr, link_bc_rcv_gap(bcl));
		msg_set_probe(hdr, probe);
		msg_set_is_keepalive(hdr, probe || probe_reply);
		if (l->peer_caps & TIPC_GAP_ACK_BLOCK)
			glen = tipc_build_gap_ack_blks(l, data);
		tipc_mon_prep(l->net, data + glen, &dlen, mstate, l->bearer_id);
		msg_set_size(hdr, INT_H_SIZE + glen + dlen);
		skb_trim(skb, INT_H_SIZE + glen + dlen);
		l->stats.sent_states++;
		l->rcv_unacked = 0;
	} else {
		/* RESET_MSG or ACTIVATE_MSG */
		if (mtyp == ACTIVATE_MSG) {
			msg_set_dest_session_valid(hdr, 1);
			msg_set_dest_session(hdr, l->peer_session);
		}
		msg_set_max_pkt(hdr, l->advertised_mtu);
		strcpy(data, l->if_name);
		msg_set_size(hdr, INT_H_SIZE + TIPC_MAX_IF_NAME);
		skb_trim(skb, INT_H_SIZE + TIPC_MAX_IF_NAME);
	}
	if (probe)
		l->stats.sent_probes++;
	if (rcvgap)
		l->stats.sent_nacks++;
	skb->priority = TC_PRIO_CONTROL;
	__skb_queue_tail(xmitq, skb);
	trace_tipc_proto_build(skb, false, l->name);
}

void tipc_link_create_dummy_tnl_msg(struct tipc_link *l,
				    struct sk_buff_head *xmitq)
{
	u32 onode = tipc_own_addr(l->net);
	struct tipc_msg *hdr, *ihdr;
	struct sk_buff_head tnlq;
	struct sk_buff *skb;
	u32 dnode = l->addr;

	__skb_queue_head_init(&tnlq);
	skb = tipc_msg_create(TUNNEL_PROTOCOL, FAILOVER_MSG,
			      INT_H_SIZE, BASIC_H_SIZE,
			      dnode, onode, 0, 0, 0);
	if (!skb) {
		pr_warn("%sunable to create tunnel packet\n", link_co_err);
		return;
	}

	hdr = buf_msg(skb);
	msg_set_msgcnt(hdr, 1);
	msg_set_bearer_id(hdr, l->peer_bearer_id);

	ihdr = (struct tipc_msg *)msg_data(hdr);
	tipc_msg_init(onode, ihdr, TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
		      BASIC_H_SIZE, dnode);
	msg_set_errcode(ihdr, TIPC_ERR_NO_PORT);
	__skb_queue_tail(&tnlq, skb);
	tipc_link_xmit(l, &tnlq, xmitq);
}

/* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
 * with contents of the link's transmit and backlog queues.
 */
void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
			   int mtyp, struct sk_buff_head *xmitq)
{
	struct sk_buff_head *fdefq = &tnl->failover_deferdq;
	struct sk_buff *skb, *tnlskb;
	struct tipc_msg *hdr, tnlhdr;
	struct sk_buff_head *queue = &l->transmq;
	struct sk_buff_head tmpxq, tnlq, frags;
	u16 pktlen, pktcnt, seqno = l->snd_nxt;
	bool pktcnt_need_update = false;
	u16 syncpt;
	int rc;

	if (!tnl)
		return;

	__skb_queue_head_init(&tnlq);
	/* Link Synching:
	 * From now on, send only one single ("dummy") SYNCH message
	 * to peer. The SYNCH message does not contain any data, just
	 * a header conveying the synch point to the peer.
	 */
	if (mtyp == SYNCH_MSG && (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
		tnlskb = tipc_msg_create(TUNNEL_PROTOCOL, SYNCH_MSG,
					 INT_H_SIZE, 0, l->addr,
					 tipc_own_addr(l->net),
					 0, 0, 0);
		if (!tnlskb) {
			pr_warn("%sunable to create dummy SYNCH_MSG\n",
				link_co_err);
			return;
		}

		hdr = buf_msg(tnlskb);
		syncpt = l->snd_nxt + skb_queue_len(&l->backlogq) - 1;
		msg_set_syncpt(hdr, syncpt);
		msg_set_bearer_id(hdr, l->peer_bearer_id);
		__skb_queue_tail(&tnlq, tnlskb);
		tipc_link_xmit(tnl, &tnlq, xmitq);
		return;
	}

	__skb_queue_head_init(&tmpxq);
	__skb_queue_head_init(&frags);
	/* At least one packet required for safe algorithm => add dummy */
	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
			      BASIC_H_SIZE, 0, l->addr, tipc_own_addr(l->net),
			      0, 0, TIPC_ERR_NO_PORT);
	if (!skb) {
		pr_warn("%sunable to create tunnel packet\n", link_co_err);
		return;
	}
	__skb_queue_tail(&tnlq, skb);
	tipc_link_xmit(l, &tnlq, &tmpxq);
	__skb_queue_purge(&tmpxq);

	/* Initialize reusable tunnel packet header */
	tipc_msg_init(tipc_own_addr(l->net), &tnlhdr, TUNNEL_PROTOCOL,
		      mtyp, INT_H_SIZE, l->addr);
	if (mtyp == SYNCH_MSG)
		pktcnt = l->snd_nxt - buf_seqno(skb_peek(&l->transmq));
	else
		pktcnt = skb_queue_len(&l->transmq);
	pktcnt += skb_queue_len(&l->backlogq);
	msg_set_msgcnt(&tnlhdr, pktcnt);
	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
tnl:
	/* Wrap each packet into a tunnel packet */
	skb_queue_walk(queue, skb) {
		hdr = buf_msg(skb);
		if (queue == &l->backlogq)
			msg_set_seqno(hdr, seqno++);
		pktlen = msg_size(hdr);

		/* Tunnel link MTU is not large enough? This could be
		 * due to:
		 * 1) Link MTU has just changed or set differently;
		 * 2) Or FAILOVER on the top of a SYNCH message
		 *
		 * The 2nd case should not happen if peer supports
		 * TIPC_TUNNEL_ENHANCED
		 */
		if (pktlen > tnl->mtu - INT_H_SIZE) {
			if (mtyp == FAILOVER_MSG &&
			    (tnl->peer_caps & TIPC_TUNNEL_ENHANCED)) {
				rc = tipc_msg_fragment(skb, &tnlhdr, tnl->mtu,
						       &frags);
				if (rc) {
					pr_warn("%sunable to frag msg: rc %d\n",
						link_co_err, rc);
					return;
				}
				pktcnt += skb_queue_len(&frags) - 1;
				pktcnt_need_update = true;
				skb_queue_splice_tail_init(&frags, &tnlq);
				continue;
			}
			/* Unluckily, peer doesn't have TIPC_TUNNEL_ENHANCED
			 * => Just warn it and return!
			 */
			pr_warn_ratelimited("%stoo large msg <%d, %d>: %d!\n",
					    link_co_err, msg_user(hdr),
					    msg_type(hdr), msg_size(hdr));
			return;
		}

		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE, GFP_ATOMIC);
		if (!tnlskb) {
			pr_warn("%sunable to send packet\n", link_co_err);
			return;
		}
		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
		__skb_queue_tail(&tnlq, tnlskb);
	}
	if (queue != &l->backlogq) {
		queue = &l->backlogq;
		goto tnl;
	}

	if (pktcnt_need_update)
		skb_queue_walk(&tnlq, skb) {
			hdr = buf_msg(skb);
			msg_set_msgcnt(hdr, pktcnt);
		}

	tipc_link_xmit(tnl, &tnlq, xmitq);

	if (mtyp == FAILOVER_MSG) {
		tnl->drop_point = l->rcv_nxt;
		tnl->failover_reasm_skb = l->reasm_buf;
		l->reasm_buf = NULL;

		/* Failover the link's deferdq */
		if (unlikely(!skb_queue_empty(fdefq))) {
			pr_warn("Link failover deferdq not empty: %d!\n",
				skb_queue_len(fdefq));
			__skb_queue_purge(fdefq);
		}
		skb_queue_splice_init(&l->deferdq, fdefq);
	}
}

/**
 * tipc_link_failover_prepare() - prepare tnl for link failover
 *
 * This is a special version of the precursor - tipc_link_tnl_prepare(),
 * see the tipc_node_link_failover() for details
 *
 * @l: failover link
 * @tnl: tunnel link
 * @xmitq: queue for messages to be xmited
 */
void tipc_link_failover_prepare(struct tipc_link *l, struct tipc_link *tnl,
				struct sk_buff_head *xmitq)
{
	struct sk_buff_head *fdefq = &tnl->failover_deferdq;

	tipc_link_create_dummy_tnl_msg(tnl, xmitq);

	/* This failover link endpoint was never established before,
	 * so it has not received anything from peer.
	 * Otherwise, it must be a normal failover situation or the
	 * node has entered SELF_DOWN_PEER_LEAVING and both peer nodes
	 * would have to start over from scratch instead.
	 */
	tnl->drop_point = 1;
	tnl->failover_reasm_skb = NULL;

	/* Initiate the link's failover deferdq */
	if (unlikely(!skb_queue_empty(fdefq))) {
		pr_warn("Link failover deferdq not empty: %d!\n",
			skb_queue_len(fdefq));
		__skb_queue_purge(fdefq);
	}
}

/* tipc_link_validate_msg(): validate message against current link state
 * Returns true if message should be accepted, otherwise false
 */
bool tipc_link_validate_msg(struct tipc_link *l, struct tipc_msg *hdr)
{
	u16 curr_session = l->peer_session;
	u16 session = msg_session(hdr);
	int mtyp = msg_type(hdr);

	if (msg_user(hdr) != LINK_PROTOCOL)
		return true;

	switch (mtyp) {
	case RESET_MSG:
		if (!l->in_session)
			return true;
		/* Accept only RESET with new session number */
		return more(session, curr_session);
	case ACTIVATE_MSG:
		if (!l->in_session)
			return true;
		/* Accept only ACTIVATE with new or current session number */
		return !less(session, curr_session);
	case STATE_MSG:
		/* Accept only STATE with current session number */
		if (!l->in_session)
			return false;
		if (session != curr_session)
			return false;
		/* Extra sanity check */
		if (!link_is_up(l) && msg_ack(hdr))
			return false;
		if (!(l->peer_caps & TIPC_LINK_PROTO_SEQNO))
			return true;
		/* Accept only STATE with new sequence number */
		return !less(msg_seqno(hdr), l->rcv_nxt_state);
	default:
		return false;
	}
}

/* tipc_link_proto_rcv(): receive link level protocol message :
 * Note that network plane id propagates through the network, and may
 * change at any time. The node with lowest numerical id determines
 * network plane
 */
static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
			       struct sk_buff_head *xmitq)
{
	struct tipc_msg *hdr = buf_msg(skb);
	struct tipc_gap_ack_blks *ga = NULL;
	u16 rcvgap = 0;
	u16 ack = msg_ack(hdr);
	u16 gap = msg_seq_gap(hdr);
	u16 peers_snd_nxt =  msg_next_sent(hdr);
	u16 peers_tol = msg_link_tolerance(hdr);
	u16 peers_prio = msg_linkprio(hdr);
	u16 rcv_nxt = l->rcv_nxt;
	u16 dlen = msg_data_sz(hdr);
	int mtyp = msg_type(hdr);
	bool reply = msg_probe(hdr);
	u16 glen = 0;
	void *data;
	char *if_name;
	int rc = 0;

	trace_tipc_proto_rcv(skb, false, l->name);
	if (tipc_link_is_blocked(l) || !xmitq)
		goto exit;

	if (tipc_own_addr(l->net) > msg_prevnode(hdr))
		l->net_plane = msg_net_plane(hdr);

	skb_linearize(skb);
	hdr = buf_msg(skb);
	data = msg_data(hdr);

	if (!tipc_link_validate_msg(l, hdr)) {
		trace_tipc_skb_dump(skb, false, "PROTO invalid (1)!");
		trace_tipc_link_dump(l, TIPC_DUMP_NONE, "PROTO invalid (1)!");
		goto exit;
	}

	switch (mtyp) {
	case RESET_MSG:
	case ACTIVATE_MSG:
		/* Complete own link name with peer's interface name */
		if_name =  strrchr(l->name, ':') + 1;
		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
			break;
		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
			break;
		strncpy(if_name, data, TIPC_MAX_IF_NAME);

		/* Update own tolerance if peer indicates a non-zero value */
		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
			l->tolerance = peers_tol;
			l->bc_rcvlink->tolerance = peers_tol;
		}
		/* Update own priority if peer's priority is higher */
		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
			l->priority = peers_prio;

		/* If peer is going down we want full re-establish cycle */
		if (msg_peer_stopping(hdr)) {
			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
			break;
		}

		/* If this endpoint was re-created while peer was ESTABLISHING
		 * it doesn't know current session number. Force re-synch.
		 */
		if (mtyp == ACTIVATE_MSG && msg_dest_session_valid(hdr) &&
		    l->session != msg_dest_session(hdr)) {
			if (less(l->session, msg_dest_session(hdr)))
				l->session = msg_dest_session(hdr) + 1;
			break;
		}

		/* ACTIVATE_MSG serves as PEER_RESET if link is already down */
		if (mtyp == RESET_MSG || !link_is_up(l))
			rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);

		/* ACTIVATE_MSG takes up link if it was already locally reset */
		if (mtyp == ACTIVATE_MSG && l->state == LINK_ESTABLISHING)
			rc = TIPC_LINK_UP_EVT;

		l->peer_session = msg_session(hdr);
		l->in_session = true;
		l->peer_bearer_id = msg_bearer_id(hdr);
		if (l->mtu > msg_max_pkt(hdr))
			l->mtu = msg_max_pkt(hdr);
		break;

	case STATE_MSG:
		l->rcv_nxt_state = msg_seqno(hdr) + 1;

		/* Update own tolerance if peer indicates a non-zero value */
		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
			l->tolerance = peers_tol;
			l->bc_rcvlink->tolerance = peers_tol;
		}
		/* Update own prio if peer indicates a different value */
		if ((peers_prio != l->priority) &&
		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
			l->priority = peers_prio;
			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
		}

		l->silent_intv_cnt = 0;
		l->stats.recv_states++;
		if (msg_probe(hdr))
			l->stats.recv_probes++;

		if (!link_is_up(l)) {
			if (l->state == LINK_ESTABLISHING)
				rc = TIPC_LINK_UP_EVT;
			break;
		}

		/* Receive Gap ACK blocks from peer if any */
		if (l->peer_caps & TIPC_GAP_ACK_BLOCK) {
			ga = (struct tipc_gap_ack_blks *)data;
			glen = ntohs(ga->len);
			/* sanity check: if failed, ignore Gap ACK blocks */
			if (glen != tipc_gap_ack_blks_sz(ga->gack_cnt))
				ga = NULL;
		}

		tipc_mon_rcv(l->net, data + glen, dlen - glen, l->addr,
			     &l->mon_state, l->bearer_id);

		/* Send NACK if peer has sent pkts we haven't received yet */
		if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
			rcvgap = peers_snd_nxt - l->rcv_nxt;
		if (rcvgap || reply)
			tipc_link_build_proto_msg(l, STATE_MSG, 0, reply,
						  rcvgap, 0, 0, xmitq);

		rc |= tipc_link_advance_transmq(l, ack, gap, ga, xmitq);

		/* If NACK, retransmit will now start at right position */
		if (gap)
			l->stats.recv_nacks++;

		tipc_link_advance_backlog(l, xmitq);
		if (unlikely(!skb_queue_empty(&l->wakeupq)))
			link_prepare_wakeup(l);
	}
exit:
	kfree_skb(skb);
	return rc;
}

/* tipc_link_build_bc_proto_msg() - create broadcast protocol message
 */
static bool tipc_link_build_bc_proto_msg(struct tipc_link *l, bool bcast,
					 u16 peers_snd_nxt,
					 struct sk_buff_head *xmitq)
{
	struct sk_buff *skb;
	struct tipc_msg *hdr;
	struct sk_buff *dfrd_skb = skb_peek(&l->deferdq);
	u16 ack = l->rcv_nxt - 1;
	u16 gap_to = peers_snd_nxt - 1;

	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
			      0, l->addr, tipc_own_addr(l->net), 0, 0, 0);
	if (!skb)
		return false;
	hdr = buf_msg(skb);
	msg_set_last_bcast(hdr, l->bc_sndlink->snd_nxt - 1);
	msg_set_bcast_ack(hdr, ack);
	msg_set_bcgap_after(hdr, ack);
	if (dfrd_skb)
		gap_to = buf_seqno(dfrd_skb) - 1;
	msg_set_bcgap_to(hdr, gap_to);
	msg_set_non_seq(hdr, bcast);
	__skb_queue_tail(xmitq, skb);
	return true;
}

/* tipc_link_build_bc_init_msg() - synchronize broadcast link endpoints.
 *
 * Give a newly added peer node the sequence number where it should
 * start receiving and acking broadcast packets.
 */
static void tipc_link_build_bc_init_msg(struct tipc_link *l,
					struct sk_buff_head *xmitq)
{
	struct sk_buff_head list;

	__skb_queue_head_init(&list);
	if (!tipc_link_build_bc_proto_msg(l->bc_rcvlink, false, 0, &list))
		return;
	msg_set_bc_ack_invalid(buf_msg(skb_peek(&list)), true);
	tipc_link_xmit(l, &list, xmitq);
}

/* tipc_link_bc_init_rcv - receive initial broadcast synch data from peer
 */
void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr)
{
	int mtyp = msg_type(hdr);
	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);

	if (link_is_up(l))
		return;

	if (msg_user(hdr) == BCAST_PROTOCOL) {
		l->rcv_nxt = peers_snd_nxt;
		l->state = LINK_ESTABLISHED;
		return;
	}

	if (l->peer_caps & TIPC_BCAST_SYNCH)
		return;

	if (msg_peer_node_is_up(hdr))
		return;

	/* Compatibility: accept older, less safe initial synch data */
	if ((mtyp == RESET_MSG) || (mtyp == ACTIVATE_MSG))
		l->rcv_nxt = peers_snd_nxt;
}

/* tipc_link_bc_sync_rcv - update rcv link according to peer's send state
 */
int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
			  struct sk_buff_head *xmitq)
{
	struct tipc_link *snd_l = l->bc_sndlink;
	u16 peers_snd_nxt = msg_bc_snd_nxt(hdr);
	u16 from = msg_bcast_ack(hdr) + 1;
	u16 to = from + msg_bc_gap(hdr) - 1;
	int rc = 0;

	if (!link_is_up(l))
		return rc;

	if (!msg_peer_node_is_up(hdr))
		return rc;

	/* Open when peer ackowledges our bcast init msg (pkt #1) */
	if (msg_ack(hdr))
		l->bc_peer_is_up = true;

	if (!l->bc_peer_is_up)
		return rc;

	l->stats.recv_nacks++;

	/* Ignore if peers_snd_nxt goes beyond receive window */
	if (more(peers_snd_nxt, l->rcv_nxt + l->window))
		return rc;

	rc = tipc_link_bc_retrans(snd_l, l, from, to, xmitq);

	l->snd_nxt = peers_snd_nxt;
	if (link_bc_rcv_gap(l))
		rc |= TIPC_LINK_SND_STATE;

	/* Return now if sender supports nack via STATE messages */
	if (l->peer_caps & TIPC_BCAST_STATE_NACK)
		return rc;

	/* Otherwise, be backwards compatible */

	if (!more(peers_snd_nxt, l->rcv_nxt)) {
		l->nack_state = BC_NACK_SND_CONDITIONAL;
		return 0;
	}

	/* Don't NACK if one was recently sent or peeked */
	if (l->nack_state == BC_NACK_SND_SUPPRESS) {
		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
		return 0;
	}

	/* Conditionally delay NACK sending until next synch rcv */
	if (l->nack_state == BC_NACK_SND_CONDITIONAL) {
		l->nack_state = BC_NACK_SND_UNCONDITIONAL;
		if ((peers_snd_nxt - l->rcv_nxt) < TIPC_MIN_LINK_WIN)
			return 0;
	}

	/* Send NACK now but suppress next one */
	tipc_link_build_bc_proto_msg(l, true, peers_snd_nxt, xmitq);
	l->nack_state = BC_NACK_SND_SUPPRESS;
	return 0;
}

void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
			  struct sk_buff_head *xmitq)
{
	struct sk_buff *skb, *tmp;
	struct tipc_link *snd_l = l->bc_sndlink;

	if (!link_is_up(l) || !l->bc_peer_is_up)
		return;

	if (!more(acked, l->acked))
		return;

	trace_tipc_link_bc_ack(l, l->acked, acked, &snd_l->transmq);
	/* Skip over packets peer has already acked */
	skb_queue_walk(&snd_l->transmq, skb) {
		if (more(buf_seqno(skb), l->acked))
			break;
	}

	/* Update/release the packets peer is acking now */
	skb_queue_walk_from_safe(&snd_l->transmq, skb, tmp) {
		if (more(buf_seqno(skb), acked))
			break;
		if (!--TIPC_SKB_CB(skb)->ackers) {
			__skb_unlink(skb, &snd_l->transmq);
			kfree_skb(skb);
		}
	}
	l->acked = acked;
	tipc_link_advance_backlog(snd_l, xmitq);
	if (unlikely(!skb_queue_empty(&snd_l->wakeupq)))
		link_prepare_wakeup(snd_l);
}

/* tipc_link_bc_nack_rcv(): receive broadcast nack message
 * This function is here for backwards compatibility, since
 * no BCAST_PROTOCOL/STATE messages occur from TIPC v2.5.
 */
int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
			  struct sk_buff_head *xmitq)
{
	struct tipc_msg *hdr = buf_msg(skb);
	u32 dnode = msg_destnode(hdr);
	int mtyp = msg_type(hdr);
	u16 acked = msg_bcast_ack(hdr);
	u16 from = acked + 1;
	u16 to = msg_bcgap_to(hdr);
	u16 peers_snd_nxt = to + 1;
	int rc = 0;

	kfree_skb(skb);

	if (!tipc_link_is_up(l) || !l->bc_peer_is_up)
		return 0;

	if (mtyp != STATE_MSG)
		return 0;

	if (dnode == tipc_own_addr(l->net)) {
		tipc_link_bc_ack_rcv(l, acked, xmitq);
		rc = tipc_link_bc_retrans(l->bc_sndlink, l, from, to, xmitq);
		l->stats.recv_nacks++;
		return rc;
	}

	/* Msg for other node => suppress own NACK at next sync if applicable */
	if (more(peers_snd_nxt, l->rcv_nxt) && !less(l->rcv_nxt, from))
		l->nack_state = BC_NACK_SND_SUPPRESS;

	return 0;
}

void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
{
	int max_bulk = TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE);

	l->window = win;
	l->backlog[TIPC_LOW_IMPORTANCE].limit      = max_t(u16, 50, win);
	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = max_t(u16, 100, win * 2);
	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = max_t(u16, 150, win * 3);
	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = max_t(u16, 200, win * 4);
	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
}

/**
 * link_reset_stats - reset link statistics
 * @l: pointer to link
 */
void tipc_link_reset_stats(struct tipc_link *l)
{
	memset(&l->stats, 0, sizeof(l->stats));
}

static void link_print(struct tipc_link *l, const char *str)
{
	struct sk_buff *hskb = skb_peek(&l->transmq);
	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt - 1;
	u16 tail = l->snd_nxt - 1;

	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
		skb_queue_len(&l->transmq), head, tail,
		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
}

/* Parse and validate nested (link) properties valid for media, bearer and link
 */
int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
{
	int err;

	err = nla_parse_nested_deprecated(props, TIPC_NLA_PROP_MAX, prop,
					  tipc_nl_prop_policy, NULL);
	if (err)
		return err;

	if (props[TIPC_NLA_PROP_PRIO]) {
		u32 prio;

		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
		if (prio > TIPC_MAX_LINK_PRI)
			return -EINVAL;
	}

	if (props[TIPC_NLA_PROP_TOL]) {
		u32 tol;

		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
			return -EINVAL;
	}

	if (props[TIPC_NLA_PROP_WIN]) {
		u32 win;

		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
			return -EINVAL;
	}

	return 0;
}

static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
{
	int i;
	struct nlattr *stats;

	struct nla_map {
		u32 key;
		u32 val;
	};

	struct nla_map map[] = {
		{TIPC_NLA_STATS_RX_INFO, 0},
		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
		{TIPC_NLA_STATS_TX_INFO, 0},
		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
			s->msg_length_counts : 1},
		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
			(s->accu_queue_sz / s->queue_sz_counts) : 0}
	};

	stats = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
	if (!stats)
		return -EMSGSIZE;

	for (i = 0; i <  ARRAY_SIZE(map); i++)
		if (nla_put_u32(skb, map[i].key, map[i].val))
			goto msg_full;

	nla_nest_end(skb, stats);

	return 0;
msg_full:
	nla_nest_cancel(skb, stats);

	return -EMSGSIZE;
}

/* Caller should hold appropriate locks to protect the link */
int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
		       struct tipc_link *link, int nlflags)
{
	u32 self = tipc_own_addr(net);
	struct nlattr *attrs;
	struct nlattr *prop;
	void *hdr;
	int err;

	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
			  nlflags, TIPC_NL_LINK_GET);
	if (!hdr)
		return -EMSGSIZE;

	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
	if (!attrs)
		goto msg_full;

	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST, tipc_cluster_mask(self)))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->stats.recv_pkts))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->stats.sent_pkts))
		goto attr_msg_full;

	if (tipc_link_is_up(link))
		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
			goto attr_msg_full;
	if (link->active)
		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
			goto attr_msg_full;

	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
	if (!prop)
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
		goto prop_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
		goto prop_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
			link->window))
		goto prop_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
		goto prop_msg_full;
	nla_nest_end(msg->skb, prop);

	err = __tipc_nl_add_stats(msg->skb, &link->stats);
	if (err)
		goto attr_msg_full;

	nla_nest_end(msg->skb, attrs);
	genlmsg_end(msg->skb, hdr);

	return 0;

prop_msg_full:
	nla_nest_cancel(msg->skb, prop);
attr_msg_full:
	nla_nest_cancel(msg->skb, attrs);
msg_full:
	genlmsg_cancel(msg->skb, hdr);

	return -EMSGSIZE;
}

static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
				      struct tipc_stats *stats)
{
	int i;
	struct nlattr *nest;

	struct nla_map {
		__u32 key;
		__u32 val;
	};

	struct nla_map map[] = {
		{TIPC_NLA_STATS_RX_INFO, stats->recv_pkts},
		{TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
		{TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
		{TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
		{TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
		{TIPC_NLA_STATS_TX_INFO, stats->sent_pkts},
		{TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
		{TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
		{TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
		{TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
		{TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
		{TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
		{TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
		{TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
		{TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
		{TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
		{TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
		{TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
		{TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
			(stats->accu_queue_sz / stats->queue_sz_counts) : 0}
	};

	nest = nla_nest_start_noflag(skb, TIPC_NLA_LINK_STATS);
	if (!nest)
		return -EMSGSIZE;

	for (i = 0; i <  ARRAY_SIZE(map); i++)
		if (nla_put_u32(skb, map[i].key, map[i].val))
			goto msg_full;

	nla_nest_end(skb, nest);

	return 0;
msg_full:
	nla_nest_cancel(skb, nest);

	return -EMSGSIZE;
}

int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
{
	int err;
	void *hdr;
	struct nlattr *attrs;
	struct nlattr *prop;
	struct tipc_net *tn = net_generic(net, tipc_net_id);
	u32 bc_mode = tipc_bcast_get_broadcast_mode(net);
	u32 bc_ratio = tipc_bcast_get_broadcast_ratio(net);
	struct tipc_link *bcl = tn->bcl;

	if (!bcl)
		return 0;

	tipc_bcast_lock(net);

	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
			  NLM_F_MULTI, TIPC_NL_LINK_GET);
	if (!hdr) {
		tipc_bcast_unlock(net);
		return -EMSGSIZE;
	}

	attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK);
	if (!attrs)
		goto msg_full;

	/* The broadcast link is always up */
	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
		goto attr_msg_full;

	if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
		goto attr_msg_full;
	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, 0))
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, 0))
		goto attr_msg_full;

	prop = nla_nest_start_noflag(msg->skb, TIPC_NLA_LINK_PROP);
	if (!prop)
		goto attr_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->window))
		goto prop_msg_full;
	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST, bc_mode))
		goto prop_msg_full;
	if (bc_mode & BCLINK_MODE_SEL)
		if (nla_put_u32(msg->skb, TIPC_NLA_PROP_BROADCAST_RATIO,
				bc_ratio))
			goto prop_msg_full;
	nla_nest_end(msg->skb, prop);

	err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
	if (err)
		goto attr_msg_full;

	tipc_bcast_unlock(net);
	nla_nest_end(msg->skb, attrs);
	genlmsg_end(msg->skb, hdr);

	return 0;

prop_msg_full:
	nla_nest_cancel(msg->skb, prop);
attr_msg_full:
	nla_nest_cancel(msg->skb, attrs);
msg_full:
	tipc_bcast_unlock(net);
	genlmsg_cancel(msg->skb, hdr);

	return -EMSGSIZE;
}

void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
			     struct sk_buff_head *xmitq)
{
	l->tolerance = tol;
	if (l->bc_rcvlink)
		l->bc_rcvlink->tolerance = tol;
	if (link_is_up(l))
		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
}

void tipc_link_set_prio(struct tipc_link *l, u32 prio,
			struct sk_buff_head *xmitq)
{
	l->priority = prio;
	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, prio, xmitq);
}

void tipc_link_set_abort_limit(struct tipc_link *l, u32 limit)
{
	l->abort_limit = limit;
}

char *tipc_link_name_ext(struct tipc_link *l, char *buf)
{
	if (!l)
		scnprintf(buf, TIPC_MAX_LINK_NAME, "null");
	else if (link_is_bc_sndlink(l))
		scnprintf(buf, TIPC_MAX_LINK_NAME, "broadcast-sender");
	else if (link_is_bc_rcvlink(l))
		scnprintf(buf, TIPC_MAX_LINK_NAME,
			  "broadcast-receiver, peer %x", l->addr);
	else
		memcpy(buf, l->name, TIPC_MAX_LINK_NAME);

	return buf;
}

/**
 * tipc_link_dump - dump TIPC link data
 * @l: tipc link to be dumped
 * @dqueues: bitmask to decide if any link queue to be dumped?
 *           - TIPC_DUMP_NONE: don't dump link queues
 *           - TIPC_DUMP_TRANSMQ: dump link transmq queue
 *           - TIPC_DUMP_BACKLOGQ: dump link backlog queue
 *           - TIPC_DUMP_DEFERDQ: dump link deferd queue
 *           - TIPC_DUMP_INPUTQ: dump link input queue
 *           - TIPC_DUMP_WAKEUP: dump link wakeup queue
 *           - TIPC_DUMP_ALL: dump all the link queues above
 * @buf: returned buffer of dump data in format
 */
int tipc_link_dump(struct tipc_link *l, u16 dqueues, char *buf)
{
	int i = 0;
	size_t sz = (dqueues) ? LINK_LMAX : LINK_LMIN;
	struct sk_buff_head *list;
	struct sk_buff *hskb, *tskb;
	u32 len;

	if (!l) {
		i += scnprintf(buf, sz, "link data: (null)\n");
		return i;
	}

	i += scnprintf(buf, sz, "link data: %x", l->addr);
	i += scnprintf(buf + i, sz - i, " %x", l->state);
	i += scnprintf(buf + i, sz - i, " %u", l->in_session);
	i += scnprintf(buf + i, sz - i, " %u", l->session);
	i += scnprintf(buf + i, sz - i, " %u", l->peer_session);
	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt);
	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt);
	i += scnprintf(buf + i, sz - i, " %u", l->snd_nxt_state);
	i += scnprintf(buf + i, sz - i, " %u", l->rcv_nxt_state);
	i += scnprintf(buf + i, sz - i, " %x", l->peer_caps);
	i += scnprintf(buf + i, sz - i, " %u", l->silent_intv_cnt);
	i += scnprintf(buf + i, sz - i, " %u", l->rst_cnt);
	i += scnprintf(buf + i, sz - i, " %u", 0);
	i += scnprintf(buf + i, sz - i, " %u", 0);
	i += scnprintf(buf + i, sz - i, " %u", l->acked);

	list = &l->transmq;
	len = skb_queue_len(list);
	hskb = skb_peek(list);
	tskb = skb_peek_tail(list);
	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);

	list = &l->deferdq;
	len = skb_queue_len(list);
	hskb = skb_peek(list);
	tskb = skb_peek_tail(list);
	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);

	list = &l->backlogq;
	len = skb_queue_len(list);
	hskb = skb_peek(list);
	tskb = skb_peek_tail(list);
	i += scnprintf(buf + i, sz - i, " | %u %u %u", len,
		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);

	list = l->inputq;
	len = skb_queue_len(list);
	hskb = skb_peek(list);
	tskb = skb_peek_tail(list);
	i += scnprintf(buf + i, sz - i, " | %u %u %u\n", len,
		       (hskb) ? msg_seqno(buf_msg(hskb)) : 0,
		       (tskb) ? msg_seqno(buf_msg(tskb)) : 0);

	if (dqueues & TIPC_DUMP_TRANSMQ) {
		i += scnprintf(buf + i, sz - i, "transmq: ");
		i += tipc_list_dump(&l->transmq, false, buf + i);
	}
	if (dqueues & TIPC_DUMP_BACKLOGQ) {
		i += scnprintf(buf + i, sz - i,
			       "backlogq: <%u %u %u %u %u>, ",
			       l->backlog[TIPC_LOW_IMPORTANCE].len,
			       l->backlog[TIPC_MEDIUM_IMPORTANCE].len,
			       l->backlog[TIPC_HIGH_IMPORTANCE].len,
			       l->backlog[TIPC_CRITICAL_IMPORTANCE].len,
			       l->backlog[TIPC_SYSTEM_IMPORTANCE].len);
		i += tipc_list_dump(&l->backlogq, false, buf + i);
	}
	if (dqueues & TIPC_DUMP_DEFERDQ) {
		i += scnprintf(buf + i, sz - i, "deferdq: ");
		i += tipc_list_dump(&l->deferdq, false, buf + i);
	}
	if (dqueues & TIPC_DUMP_INPUTQ) {
		i += scnprintf(buf + i, sz - i, "inputq: ");
		i += tipc_list_dump(l->inputq, false, buf + i);
	}
	if (dqueues & TIPC_DUMP_WAKEUP) {
		i += scnprintf(buf + i, sz - i, "wakeup: ");
		i += tipc_list_dump(&l->wakeupq, false, buf + i);
	}

	return i;
}