summaryrefslogtreecommitdiffstats
path: root/net/sctp/sm_make_chunk.c
blob: 479a70ef6ff8abe2a59a16ddc672f6638c7b3369 (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
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001-2002 Intel Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions work with the state functions in sctp_sm_statefuns.c
 * to implement the state operations.  These functions implement the
 * steps which require modifying existing data structures.
 *
 * This SCTP implementation 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, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    C. Robin              <chris@hundredacre.ac.uk>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Xingang Guo           <xingang.guo@intel.com>
 *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
 *    Sridhar Samudrala	    <sri@us.ibm.com>
 *    Daisy Chang	    <daisyc@us.ibm.com>
 *    Ardelle Fan	    <ardelle.fan@intel.com>
 *    Kevin Gao             <kevin.gao@intel.com>
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/slab.h>
#include <net/sock.h>

#include <linux/skbuff.h>
#include <linux/random.h>	/* for get_random_bytes */
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

SCTP_STATIC
struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
				   __u8 type, __u8 flags, int paylen);
static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
					const struct sctp_association *asoc,
					const struct sctp_chunk *init_chunk,
					int *cookie_len,
					const __u8 *raw_addrs, int addrs_len);
static int sctp_process_param(struct sctp_association *asoc,
			      union sctp_params param,
			      const union sctp_addr *peer_addr,
			      gfp_t gfp);
static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
			      const void *data);

/* What was the inbound interface for this chunk? */
int sctp_chunk_iif(const struct sctp_chunk *chunk)
{
	struct sctp_af *af;
	int iif = 0;

	af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
	if (af)
		iif = af->skb_iif(chunk->skb);

	return iif;
}

/* RFC 2960 3.3.2 Initiation (INIT) (1)
 *
 * Note 2: The ECN capable field is reserved for future use of
 * Explicit Congestion Notification.
 */
static const struct sctp_paramhdr ecap_param = {
	SCTP_PARAM_ECN_CAPABLE,
	cpu_to_be16(sizeof(struct sctp_paramhdr)),
};
static const struct sctp_paramhdr prsctp_param = {
	SCTP_PARAM_FWD_TSN_SUPPORT,
	cpu_to_be16(sizeof(struct sctp_paramhdr)),
};

/* A helper to initialize an op error inside a
 * provided chunk, as most cause codes will be embedded inside an
 * abort chunk.
 */
void  sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
		      size_t paylen)
{
	sctp_errhdr_t err;
	__u16 len;

	/* Cause code constants are now defined in network order.  */
	err.cause = cause_code;
	len = sizeof(sctp_errhdr_t) + paylen;
	err.length  = htons(len);
	chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(sctp_errhdr_t), &err);
}

/* A helper to initialize an op error inside a
 * provided chunk, as most cause codes will be embedded inside an
 * abort chunk.  Differs from sctp_init_cause in that it won't oops
 * if there isn't enough space in the op error chunk
 */
static int sctp_init_cause_fixed(struct sctp_chunk *chunk, __be16 cause_code,
		      size_t paylen)
{
	sctp_errhdr_t err;
	__u16 len;

	/* Cause code constants are now defined in network order.  */
	err.cause = cause_code;
	len = sizeof(sctp_errhdr_t) + paylen;
	err.length  = htons(len);

	if (skb_tailroom(chunk->skb) < len)
		return -ENOSPC;
	chunk->subh.err_hdr = sctp_addto_chunk_fixed(chunk,
						     sizeof(sctp_errhdr_t),
						     &err);
	return 0;
}
/* 3.3.2 Initiation (INIT) (1)
 *
 * This chunk is used to initiate a SCTP association between two
 * endpoints. The format of the INIT chunk is shown below:
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                         Initiate Tag                          |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |           Advertised Receiver Window Credit (a_rwnd)          |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                          Initial TSN                          |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    \                                                               \
 *    /              Optional/Variable-Length Parameters              /
 *    \                                                               \
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 *
 * The INIT chunk contains the following parameters. Unless otherwise
 * noted, each parameter MUST only be included once in the INIT chunk.
 *
 * Fixed Parameters                     Status
 * ----------------------------------------------
 * Initiate Tag                        Mandatory
 * Advertised Receiver Window Credit   Mandatory
 * Number of Outbound Streams          Mandatory
 * Number of Inbound Streams           Mandatory
 * Initial TSN                         Mandatory
 *
 * Variable Parameters                  Status     Type Value
 * -------------------------------------------------------------
 * IPv4 Address (Note 1)               Optional    5
 * IPv6 Address (Note 1)               Optional    6
 * Cookie Preservative                 Optional    9
 * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
 * Host Name Address (Note 3)          Optional    11
 * Supported Address Types (Note 4)    Optional    12
 */
struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
			     const struct sctp_bind_addr *bp,
			     gfp_t gfp, int vparam_len)
{
	sctp_inithdr_t init;
	union sctp_params addrs;
	size_t chunksize;
	struct sctp_chunk *retval = NULL;
	int num_types, addrs_len = 0;
	struct sctp_sock *sp;
	sctp_supported_addrs_param_t sat;
	__be16 types[2];
	sctp_adaptation_ind_param_t aiparam;
	sctp_supported_ext_param_t ext_param;
	int num_ext = 0;
	__u8 extensions[3];
	sctp_paramhdr_t *auth_chunks = NULL,
			*auth_hmacs = NULL;

	/* RFC 2960 3.3.2 Initiation (INIT) (1)
	 *
	 * Note 1: The INIT chunks can contain multiple addresses that
	 * can be IPv4 and/or IPv6 in any combination.
	 */
	retval = NULL;

	/* Convert the provided bind address list to raw format. */
	addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);

	init.init_tag		   = htonl(asoc->c.my_vtag);
	init.a_rwnd		   = htonl(asoc->rwnd);
	init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
	init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
	init.initial_tsn	   = htonl(asoc->c.initial_tsn);

	/* How many address types are needed? */
	sp = sctp_sk(asoc->base.sk);
	num_types = sp->pf->supported_addrs(sp, types);

	chunksize = sizeof(init) + addrs_len;
	chunksize += WORD_ROUND(SCTP_SAT_LEN(num_types));
	chunksize += sizeof(ecap_param);

	if (sctp_prsctp_enable)
		chunksize += sizeof(prsctp_param);

	/* ADDIP: Section 4.2.7:
	 *  An implementation supporting this extension [ADDIP] MUST list
	 *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
	 *  INIT-ACK parameters.
	 */
	if (sctp_addip_enable) {
		extensions[num_ext] = SCTP_CID_ASCONF;
		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
		num_ext += 2;
	}

	if (sp->adaptation_ind)
		chunksize += sizeof(aiparam);

	chunksize += vparam_len;

	/* Account for AUTH related parameters */
	if (sctp_auth_enable) {
		/* Add random parameter length*/
		chunksize += sizeof(asoc->c.auth_random);

		/* Add HMACS parameter length if any were defined */
		auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
		if (auth_hmacs->length)
			chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
		else
			auth_hmacs = NULL;

		/* Add CHUNKS parameter length */
		auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
		if (auth_chunks->length)
			chunksize += WORD_ROUND(ntohs(auth_chunks->length));
		else
			auth_chunks = NULL;

		extensions[num_ext] = SCTP_CID_AUTH;
		num_ext += 1;
	}

	/* If we have any extensions to report, account for that */
	if (num_ext)
		chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
					num_ext);

	/* RFC 2960 3.3.2 Initiation (INIT) (1)
	 *
	 * Note 3: An INIT chunk MUST NOT contain more than one Host
	 * Name address parameter. Moreover, the sender of the INIT
	 * MUST NOT combine any other address types with the Host Name
	 * address in the INIT. The receiver of INIT MUST ignore any
	 * other address types if the Host Name address parameter is
	 * present in the received INIT chunk.
	 *
	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
	 */

	retval = sctp_make_chunk(asoc, SCTP_CID_INIT, 0, chunksize);
	if (!retval)
		goto nodata;

	retval->subh.init_hdr =
		sctp_addto_chunk(retval, sizeof(init), &init);
	retval->param_hdr.v =
		sctp_addto_chunk(retval, addrs_len, addrs.v);

	/* RFC 2960 3.3.2 Initiation (INIT) (1)
	 *
	 * Note 4: This parameter, when present, specifies all the
	 * address types the sending endpoint can support. The absence
	 * of this parameter indicates that the sending endpoint can
	 * support any address type.
	 */
	sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
	sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
	sctp_addto_chunk(retval, sizeof(sat), &sat);
	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);

	sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);

	/* Add the supported extensions parameter.  Be nice and add this
	 * fist before addiding the parameters for the extensions themselves
	 */
	if (num_ext) {
		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
		ext_param.param_hdr.length =
			    htons(sizeof(sctp_supported_ext_param_t) + num_ext);
		sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
				&ext_param);
		sctp_addto_param(retval, num_ext, extensions);
	}

	if (sctp_prsctp_enable)
		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);

	if (sp->adaptation_ind) {
		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
		aiparam.param_hdr.length = htons(sizeof(aiparam));
		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
	}

	/* Add SCTP-AUTH chunks to the parameter list */
	if (sctp_auth_enable) {
		sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
				 asoc->c.auth_random);
		if (auth_hmacs)
			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
					auth_hmacs);
		if (auth_chunks)
			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
					auth_chunks);
	}
nodata:
	kfree(addrs.v);
	return retval;
}

struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
				 const struct sctp_chunk *chunk,
				 gfp_t gfp, int unkparam_len)
{
	sctp_inithdr_t initack;
	struct sctp_chunk *retval;
	union sctp_params addrs;
	struct sctp_sock *sp;
	int addrs_len;
	sctp_cookie_param_t *cookie;
	int cookie_len;
	size_t chunksize;
	sctp_adaptation_ind_param_t aiparam;
	sctp_supported_ext_param_t ext_param;
	int num_ext = 0;
	__u8 extensions[3];
	sctp_paramhdr_t *auth_chunks = NULL,
			*auth_hmacs = NULL,
			*auth_random = NULL;

	retval = NULL;

	/* Note: there may be no addresses to embed. */
	addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);

	initack.init_tag	        = htonl(asoc->c.my_vtag);
	initack.a_rwnd			= htonl(asoc->rwnd);
	initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
	initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
	initack.initial_tsn		= htonl(asoc->c.initial_tsn);

	/* FIXME:  We really ought to build the cookie right
	 * into the packet instead of allocating more fresh memory.
	 */
	cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
				  addrs.v, addrs_len);
	if (!cookie)
		goto nomem_cookie;

	/* Calculate the total size of allocation, include the reserved
	 * space for reporting unknown parameters if it is specified.
	 */
	sp = sctp_sk(asoc->base.sk);
	chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;

	/* Tell peer that we'll do ECN only if peer advertised such cap.  */
	if (asoc->peer.ecn_capable)
		chunksize += sizeof(ecap_param);

	if (asoc->peer.prsctp_capable)
		chunksize += sizeof(prsctp_param);

	if (asoc->peer.asconf_capable) {
		extensions[num_ext] = SCTP_CID_ASCONF;
		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
		num_ext += 2;
	}

	if (sp->adaptation_ind)
		chunksize += sizeof(aiparam);

	if (asoc->peer.auth_capable) {
		auth_random = (sctp_paramhdr_t *)asoc->c.auth_random;
		chunksize += ntohs(auth_random->length);

		auth_hmacs = (sctp_paramhdr_t *)asoc->c.auth_hmacs;
		if (auth_hmacs->length)
			chunksize += WORD_ROUND(ntohs(auth_hmacs->length));
		else
			auth_hmacs = NULL;

		auth_chunks = (sctp_paramhdr_t *)asoc->c.auth_chunks;
		if (auth_chunks->length)
			chunksize += WORD_ROUND(ntohs(auth_chunks->length));
		else
			auth_chunks = NULL;

		extensions[num_ext] = SCTP_CID_AUTH;
		num_ext += 1;
	}

	if (num_ext)
		chunksize += WORD_ROUND(sizeof(sctp_supported_ext_param_t) +
					num_ext);

	/* Now allocate and fill out the chunk.  */
	retval = sctp_make_chunk(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
	if (!retval)
		goto nomem_chunk;

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [INIT ACK back to where the INIT came from.]
	 */
	retval->transport = chunk->transport;

	retval->subh.init_hdr =
		sctp_addto_chunk(retval, sizeof(initack), &initack);
	retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
	sctp_addto_chunk(retval, cookie_len, cookie);
	if (asoc->peer.ecn_capable)
		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
	if (num_ext) {
		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
		ext_param.param_hdr.length =
			    htons(sizeof(sctp_supported_ext_param_t) + num_ext);
		sctp_addto_chunk(retval, sizeof(sctp_supported_ext_param_t),
				 &ext_param);
		sctp_addto_param(retval, num_ext, extensions);
	}
	if (asoc->peer.prsctp_capable)
		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);

	if (sp->adaptation_ind) {
		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
		aiparam.param_hdr.length = htons(sizeof(aiparam));
		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
	}

	if (asoc->peer.auth_capable) {
		sctp_addto_chunk(retval, ntohs(auth_random->length),
				 auth_random);
		if (auth_hmacs)
			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
					auth_hmacs);
		if (auth_chunks)
			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
					auth_chunks);
	}

	/* We need to remove the const qualifier at this point.  */
	retval->asoc = (struct sctp_association *) asoc;

nomem_chunk:
	kfree(cookie);
nomem_cookie:
	kfree(addrs.v);
	return retval;
}

/* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
 *
 * This chunk is used only during the initialization of an association.
 * It is sent by the initiator of an association to its peer to complete
 * the initialization process. This chunk MUST precede any DATA chunk
 * sent within the association, but MAY be bundled with one or more DATA
 * chunks in the same packet.
 *
 *      0                   1                   2                   3
 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |   Type = 10   |Chunk  Flags   |         Length                |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     /                     Cookie                                    /
 *     \                                                               \
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * Chunk Flags: 8 bit
 *
 *   Set to zero on transmit and ignored on receipt.
 *
 * Length: 16 bits (unsigned integer)
 *
 *   Set to the size of the chunk in bytes, including the 4 bytes of
 *   the chunk header and the size of the Cookie.
 *
 * Cookie: variable size
 *
 *   This field must contain the exact cookie received in the
 *   State Cookie parameter from the previous INIT ACK.
 *
 *   An implementation SHOULD make the cookie as small as possible
 *   to insure interoperability.
 */
struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
				    const struct sctp_chunk *chunk)
{
	struct sctp_chunk *retval;
	void *cookie;
	int cookie_len;

	cookie = asoc->peer.cookie;
	cookie_len = asoc->peer.cookie_len;

	/* Build a cookie echo chunk.  */
	retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
	if (!retval)
		goto nodata;
	retval->subh.cookie_hdr =
		sctp_addto_chunk(retval, cookie_len, cookie);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [COOKIE ECHO back to where the INIT ACK came from.]
	 */
	if (chunk)
		retval->transport = chunk->transport;

nodata:
	return retval;
}

/* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
 *
 * This chunk is used only during the initialization of an
 * association.  It is used to acknowledge the receipt of a COOKIE
 * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
 * within the association, but MAY be bundled with one or more DATA
 * chunks or SACK chunk in the same SCTP packet.
 *
 *      0                   1                   2                   3
 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * Chunk Flags: 8 bits
 *
 *   Set to zero on transmit and ignored on receipt.
 */
struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
				   const struct sctp_chunk *chunk)
{
	struct sctp_chunk *retval;

	retval = sctp_make_chunk(asoc, SCTP_CID_COOKIE_ACK, 0, 0);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [COOKIE ACK back to where the COOKIE ECHO came from.]
	 */
	if (retval && chunk)
		retval->transport = chunk->transport;

	return retval;
}

/*
 *  Appendix A: Explicit Congestion Notification:
 *  CWR:
 *
 *  RFC 2481 details a specific bit for a sender to send in the header of
 *  its next outbound TCP segment to indicate to its peer that it has
 *  reduced its congestion window.  This is termed the CWR bit.  For
 *  SCTP the same indication is made by including the CWR chunk.
 *  This chunk contains one data element, i.e. the TSN number that
 *  was sent in the ECNE chunk.  This element represents the lowest
 *  TSN number in the datagram that was originally marked with the
 *  CE bit.
 *
 *     0                   1                   2                   3
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |                      Lowest TSN Number                        |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 *     Note: The CWR is considered a Control chunk.
 */
struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
			    const __u32 lowest_tsn,
			    const struct sctp_chunk *chunk)
{
	struct sctp_chunk *retval;
	sctp_cwrhdr_t cwr;

	cwr.lowest_tsn = htonl(lowest_tsn);
	retval = sctp_make_chunk(asoc, SCTP_CID_ECN_CWR, 0,
				 sizeof(sctp_cwrhdr_t));

	if (!retval)
		goto nodata;

	retval->subh.ecn_cwr_hdr =
		sctp_addto_chunk(retval, sizeof(cwr), &cwr);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [Report a reduced congestion window back to where the ECNE
	 * came from.]
	 */
	if (chunk)
		retval->transport = chunk->transport;

nodata:
	return retval;
}

/* Make an ECNE chunk.  This is a congestion experienced report.  */
struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
			     const __u32 lowest_tsn)
{
	struct sctp_chunk *retval;
	sctp_ecnehdr_t ecne;

	ecne.lowest_tsn = htonl(lowest_tsn);
	retval = sctp_make_chunk(asoc, SCTP_CID_ECN_ECNE, 0,
				 sizeof(sctp_ecnehdr_t));
	if (!retval)
		goto nodata;
	retval->subh.ecne_hdr =
		sctp_addto_chunk(retval, sizeof(ecne), &ecne);

nodata:
	return retval;
}

/* Make a DATA chunk for the given association from the provided
 * parameters.  However, do not populate the data payload.
 */
struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
				       const struct sctp_sndrcvinfo *sinfo,
				       int data_len, __u8 flags, __u16 ssn)
{
	struct sctp_chunk *retval;
	struct sctp_datahdr dp;
	int chunk_len;

	/* We assign the TSN as LATE as possible, not here when
	 * creating the chunk.
	 */
	dp.tsn = 0;
	dp.stream = htons(sinfo->sinfo_stream);
	dp.ppid   = sinfo->sinfo_ppid;

	/* Set the flags for an unordered send.  */
	if (sinfo->sinfo_flags & SCTP_UNORDERED) {
		flags |= SCTP_DATA_UNORDERED;
		dp.ssn = 0;
	} else
		dp.ssn = htons(ssn);

	chunk_len = sizeof(dp) + data_len;
	retval = sctp_make_chunk(asoc, SCTP_CID_DATA, flags, chunk_len);
	if (!retval)
		goto nodata;

	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));

nodata:
	return retval;
}

/* Create a selective ackowledgement (SACK) for the given
 * association.  This reports on which TSN's we've seen to date,
 * including duplicates and gaps.
 */
struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
{
	struct sctp_chunk *retval;
	struct sctp_sackhdr sack;
	int len;
	__u32 ctsn;
	__u16 num_gabs, num_dup_tsns;
	struct sctp_association *aptr = (struct sctp_association *)asoc;
	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
	struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
	struct sctp_transport *trans;

	memset(gabs, 0, sizeof(gabs));
	ctsn = sctp_tsnmap_get_ctsn(map);
	SCTP_DEBUG_PRINTK("sackCTSNAck sent:  0x%x.\n", ctsn);

	/* How much room is needed in the chunk? */
	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
	num_dup_tsns = sctp_tsnmap_num_dups(map);

	/* Initialize the SACK header.  */
	sack.cum_tsn_ack	    = htonl(ctsn);
	sack.a_rwnd 		    = htonl(asoc->a_rwnd);
	sack.num_gap_ack_blocks     = htons(num_gabs);
	sack.num_dup_tsns           = htons(num_dup_tsns);

	len = sizeof(sack)
		+ sizeof(struct sctp_gap_ack_block) * num_gabs
		+ sizeof(__u32) * num_dup_tsns;

	/* Create the chunk.  */
	retval = sctp_make_chunk(asoc, SCTP_CID_SACK, 0, len);
	if (!retval)
		goto nodata;

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, etc.) to the same destination transport
	 * address from which it received the DATA or control chunk to
	 * which it is replying.  This rule should also be followed if
	 * the endpoint is bundling DATA chunks together with the
	 * reply chunk.
	 *
	 * However, when acknowledging multiple DATA chunks received
	 * in packets from different source addresses in a single
	 * SACK, the SACK chunk may be transmitted to one of the
	 * destination transport addresses from which the DATA or
	 * control chunks being acknowledged were received.
	 *
	 * [BUG:  We do not implement the following paragraph.
	 * Perhaps we should remember the last transport we used for a
	 * SACK and avoid that (if possible) if we have seen any
	 * duplicates. --piggy]
	 *
	 * When a receiver of a duplicate DATA chunk sends a SACK to a
	 * multi- homed endpoint it MAY be beneficial to vary the
	 * destination address and not use the source address of the
	 * DATA chunk.  The reason being that receiving a duplicate
	 * from a multi-homed endpoint might indicate that the return
	 * path (as specified in the source address of the DATA chunk)
	 * for the SACK is broken.
	 *
	 * [Send to the address from which we last received a DATA chunk.]
	 */
	retval->transport = asoc->peer.last_data_from;

	retval->subh.sack_hdr =
		sctp_addto_chunk(retval, sizeof(sack), &sack);

	/* Add the gap ack block information.   */
	if (num_gabs)
		sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
				 gabs);

	/* Add the duplicate TSN information.  */
	if (num_dup_tsns)
		sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
				 sctp_tsnmap_get_dups(map));

	/* Once we have a sack generated, check to see what our sack
	 * generation is, if its 0, reset the transports to 0, and reset
	 * the association generation to 1
	 *
	 * The idea is that zero is never used as a valid generation for the
	 * association so no transport will match after a wrap event like this,
	 * Until the next sack
	 */
	if (++aptr->peer.sack_generation == 0) {
		list_for_each_entry(trans, &asoc->peer.transport_addr_list,
				    transports)
			trans->sack_generation = 0;
		aptr->peer.sack_generation = 1;
	}
nodata:
	return retval;
}

/* Make a SHUTDOWN chunk. */
struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
				      const struct sctp_chunk *chunk)
{
	struct sctp_chunk *retval;
	sctp_shutdownhdr_t shut;
	__u32 ctsn;

	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
	shut.cum_tsn_ack = htonl(ctsn);

	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN, 0,
				 sizeof(sctp_shutdownhdr_t));
	if (!retval)
		goto nodata;

	retval->subh.shutdown_hdr =
		sctp_addto_chunk(retval, sizeof(shut), &shut);

	if (chunk)
		retval->transport = chunk->transport;
nodata:
	return retval;
}

struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
				     const struct sctp_chunk *chunk)
{
	struct sctp_chunk *retval;

	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [ACK back to where the SHUTDOWN came from.]
	 */
	if (retval && chunk)
		retval->transport = chunk->transport;

	return retval;
}

struct sctp_chunk *sctp_make_shutdown_complete(
	const struct sctp_association *asoc,
	const struct sctp_chunk *chunk)
{
	struct sctp_chunk *retval;
	__u8 flags = 0;

	/* Set the T-bit if we have no association (vtag will be
	 * reflected)
	 */
	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;

	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
	 * came from.]
	 */
	if (retval && chunk)
		retval->transport = chunk->transport;

	return retval;
}

/* Create an ABORT.  Note that we set the T bit if we have no
 * association, except when responding to an INIT (sctpimpguide 2.41).
 */
struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
			      const struct sctp_chunk *chunk,
			      const size_t hint)
{
	struct sctp_chunk *retval;
	__u8 flags = 0;

	/* Set the T-bit if we have no association and 'chunk' is not
	 * an INIT (vtag will be reflected).
	 */
	if (!asoc) {
		if (chunk && chunk->chunk_hdr &&
		    chunk->chunk_hdr->type == SCTP_CID_INIT)
			flags = 0;
		else
			flags = SCTP_CHUNK_FLAG_T;
	}

	retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [ABORT back to where the offender came from.]
	 */
	if (retval && chunk)
		retval->transport = chunk->transport;

	return retval;
}

/* Helper to create ABORT with a NO_USER_DATA error.  */
struct sctp_chunk *sctp_make_abort_no_data(
	const struct sctp_association *asoc,
	const struct sctp_chunk *chunk, __u32 tsn)
{
	struct sctp_chunk *retval;
	__be32 payload;

	retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t)
				 + sizeof(tsn));

	if (!retval)
		goto no_mem;

	/* Put the tsn back into network byte order.  */
	payload = htonl(tsn);
	sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
	sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [ABORT back to where the offender came from.]
	 */
	if (chunk)
		retval->transport = chunk->transport;

no_mem:
	return retval;
}

/* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
					const struct msghdr *msg,
					size_t paylen)
{
	struct sctp_chunk *retval;
	void *payload = NULL;
	int err;

	retval = sctp_make_abort(asoc, NULL, sizeof(sctp_errhdr_t) + paylen);
	if (!retval)
		goto err_chunk;

	if (paylen) {
		/* Put the msg_iov together into payload.  */
		payload = kmalloc(paylen, GFP_KERNEL);
		if (!payload)
			goto err_payload;

		err = memcpy_fromiovec(payload, msg->msg_iov, paylen);
		if (err < 0)
			goto err_copy;
	}

	sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
	sctp_addto_chunk(retval, paylen, payload);

	if (paylen)
		kfree(payload);

	return retval;

err_copy:
	kfree(payload);
err_payload:
	sctp_chunk_free(retval);
	retval = NULL;
err_chunk:
	return retval;
}

/* Append bytes to the end of a parameter.  Will panic if chunk is not big
 * enough.
 */
static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
			      const void *data)
{
	void *target;
	int chunklen = ntohs(chunk->chunk_hdr->length);

	target = skb_put(chunk->skb, len);

	if (data)
		memcpy(target, data, len);
	else
		memset(target, 0, len);

	/* Adjust the chunk length field.  */
	chunk->chunk_hdr->length = htons(chunklen + len);
	chunk->chunk_end = skb_tail_pointer(chunk->skb);

	return target;
}

/* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
struct sctp_chunk *sctp_make_abort_violation(
	const struct sctp_association *asoc,
	const struct sctp_chunk *chunk,
	const __u8   *payload,
	const size_t paylen)
{
	struct sctp_chunk  *retval;
	struct sctp_paramhdr phdr;

	retval = sctp_make_abort(asoc, chunk, sizeof(sctp_errhdr_t) + paylen
					+ sizeof(sctp_paramhdr_t));
	if (!retval)
		goto end;

	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen
					+ sizeof(sctp_paramhdr_t));

	phdr.type = htons(chunk->chunk_hdr->type);
	phdr.length = chunk->chunk_hdr->length;
	sctp_addto_chunk(retval, paylen, payload);
	sctp_addto_param(retval, sizeof(sctp_paramhdr_t), &phdr);

end:
	return retval;
}

struct sctp_chunk *sctp_make_violation_paramlen(
	const struct sctp_association *asoc,
	const struct sctp_chunk *chunk,
	struct sctp_paramhdr *param)
{
	struct sctp_chunk *retval;
	static const char error[] = "The following parameter had invalid length:";
	size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
				sizeof(sctp_paramhdr_t);

	retval = sctp_make_abort(asoc, chunk, payload_len);
	if (!retval)
		goto nodata;

	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
			sizeof(error) + sizeof(sctp_paramhdr_t));
	sctp_addto_chunk(retval, sizeof(error), error);
	sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);

nodata:
	return retval;
}

/* Make a HEARTBEAT chunk.  */
struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
				  const struct sctp_transport *transport)
{
	struct sctp_chunk *retval;
	sctp_sender_hb_info_t hbinfo;

	retval = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));

	if (!retval)
		goto nodata;

	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
	hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t));
	hbinfo.daddr = transport->ipaddr;
	hbinfo.sent_at = jiffies;
	hbinfo.hb_nonce = transport->hb_nonce;

	/* Cast away the 'const', as this is just telling the chunk
	 * what transport it belongs to.
	 */
	retval->transport = (struct sctp_transport *) transport;
	retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
						&hbinfo);

nodata:
	return retval;
}

struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
				      const struct sctp_chunk *chunk,
				      const void *payload, const size_t paylen)
{
	struct sctp_chunk *retval;

	retval  = sctp_make_chunk(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
	if (!retval)
		goto nodata;

	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, * etc.) to the same destination transport
	 * address from which it * received the DATA or control chunk
	 * to which it is replying.
	 *
	 * [HBACK back to where the HEARTBEAT came from.]
	 */
	if (chunk)
		retval->transport = chunk->transport;

nodata:
	return retval;
}

/* Create an Operation Error chunk with the specified space reserved.
 * This routine can be used for containing multiple causes in the chunk.
 */
static struct sctp_chunk *sctp_make_op_error_space(
	const struct sctp_association *asoc,
	const struct sctp_chunk *chunk,
	size_t size)
{
	struct sctp_chunk *retval;

	retval = sctp_make_chunk(asoc, SCTP_CID_ERROR, 0,
				 sizeof(sctp_errhdr_t) + size);
	if (!retval)
		goto nodata;

	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
	 *
	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
	 * HEARTBEAT ACK, etc.) to the same destination transport
	 * address from which it received the DATA or control chunk
	 * to which it is replying.
	 *
	 */
	if (chunk)
		retval->transport = chunk->transport;

nodata:
	return retval;
}

/* Create an Operation Error chunk of a fixed size,
 * specifically, max(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT)
 * This is a helper function to allocate an error chunk for
 * for those invalid parameter codes in which we may not want
 * to report all the errors, if the incomming chunk is large
 */
static inline struct sctp_chunk *sctp_make_op_error_fixed(
	const struct sctp_association *asoc,
	const struct sctp_chunk *chunk)
{
	size_t size = asoc ? asoc->pathmtu : 0;

	if (!size)
		size = SCTP_DEFAULT_MAXSEGMENT;

	return sctp_make_op_error_space(asoc, chunk, size);
}

/* Create an Operation Error chunk.  */
struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
				 const struct sctp_chunk *chunk,
				 __be16 cause_code, const void *payload,
				 size_t paylen, size_t reserve_tail)
{
	struct sctp_chunk *retval;

	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
	if (!retval)
		goto nodata;

	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
	sctp_addto_chunk(retval, paylen, payload);
	if (reserve_tail)
		sctp_addto_param(retval, reserve_tail, NULL);

nodata:
	return retval;
}

struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
{
	struct sctp_chunk *retval;
	struct sctp_hmac *hmac_desc;
	struct sctp_authhdr auth_hdr;
	__u8 *hmac;

	/* Get the first hmac that the peer told us to use */
	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
	if (unlikely(!hmac_desc))
		return NULL;

	retval = sctp_make_chunk(asoc, SCTP_CID_AUTH, 0,
			hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
	if (!retval)
		return NULL;

	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
	auth_hdr.shkey_id = htons(asoc->active_key_id);

	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(sctp_authhdr_t),
						&auth_hdr);

	hmac = skb_put(retval->skb, hmac_desc->hmac_len);
	memset(hmac, 0, hmac_desc->hmac_len);

	/* Adjust the chunk header to include the empty MAC */
	retval->chunk_hdr->length =
		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
	retval->chunk_end = skb_tail_pointer(retval->skb);

	return retval;
}


/********************************************************************
 * 2nd Level Abstractions
 ********************************************************************/

/* Turn an skb into a chunk.
 * FIXME: Eventually move the structure directly inside the skb->cb[].
 */
struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
			    const struct sctp_association *asoc,
			    struct sock *sk)
{
	struct sctp_chunk *retval;

	retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);

	if (!retval)
		goto nodata;

	if (!sk) {
		SCTP_DEBUG_PRINTK("chunkifying skb %p w/o an sk\n", skb);
	}

	INIT_LIST_HEAD(&retval->list);
	retval->skb		= skb;
	retval->asoc		= (struct sctp_association *)asoc;
	retval->has_tsn		= 0;
	retval->has_ssn         = 0;
	retval->rtt_in_progress	= 0;
	retval->sent_at		= 0;
	retval->singleton	= 1;
	retval->end_of_packet	= 0;
	retval->ecn_ce_done	= 0;
	retval->pdiscard	= 0;

	/* sctpimpguide-05.txt Section 2.8.2
	 * M1) Each time a new DATA chunk is transmitted
	 * set the 'TSN.Missing.Report' count for that TSN to 0. The
	 * 'TSN.Missing.Report' count will be used to determine missing chunks
	 * and when to fast retransmit.
	 */
	retval->tsn_missing_report = 0;
	retval->tsn_gap_acked = 0;
	retval->fast_retransmit = SCTP_CAN_FRTX;

	/* If this is a fragmented message, track all fragments
	 * of the message (for SEND_FAILED).
	 */
	retval->msg = NULL;

	/* Polish the bead hole.  */
	INIT_LIST_HEAD(&retval->transmitted_list);
	INIT_LIST_HEAD(&retval->frag_list);
	SCTP_DBG_OBJCNT_INC(chunk);
	atomic_set(&retval->refcnt, 1);

nodata:
	return retval;
}

/* Set chunk->source and dest based on the IP header in chunk->skb.  */
void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
		     union sctp_addr *dest)
{
	memcpy(&chunk->source, src, sizeof(union sctp_addr));
	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
}

/* Extract the source address from a chunk.  */
const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
{
	/* If we have a known transport, use that.  */
	if (chunk->transport) {
		return &chunk->transport->ipaddr;
	} else {
		/* Otherwise, extract it from the IP header.  */
		return &chunk->source;
	}
}

/* Create a new chunk, setting the type and flags headers from the
 * arguments, reserving enough space for a 'paylen' byte payload.
 */
SCTP_STATIC
struct sctp_chunk *sctp_make_chunk(const struct sctp_association *asoc,
				   __u8 type, __u8 flags, int paylen)
{
	struct sctp_chunk *retval;
	sctp_chunkhdr_t *chunk_hdr;
	struct sk_buff *skb;
	struct sock *sk;

	/* No need to allocate LL here, as this is only a chunk. */
	skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
			GFP_ATOMIC);
	if (!skb)
		goto nodata;

	/* Make room for the chunk header.  */
	chunk_hdr = (sctp_chunkhdr_t *)skb_put(skb, sizeof(sctp_chunkhdr_t));
	chunk_hdr->type	  = type;
	chunk_hdr->flags  = flags;
	chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));

	sk = asoc ? asoc->base.sk : NULL;
	retval = sctp_chunkify(skb, asoc, sk);
	if (!retval) {
		kfree_skb(skb);
		goto nodata;
	}

	retval->chunk_hdr = chunk_hdr;
	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(struct sctp_chunkhdr);

	/* Determine if the chunk needs to be authenticated */
	if (sctp_auth_send_cid(type, asoc))
		retval->auth = 1;

	/* Set the skb to the belonging sock for accounting.  */
	skb->sk = sk;

	return retval;
nodata:
	return NULL;
}


/* Release the memory occupied by a chunk.  */
static void sctp_chunk_destroy(struct sctp_chunk *chunk)
{
	BUG_ON(!list_empty(&chunk->list));
	list_del_init(&chunk->transmitted_list);

	/* Free the chunk skb data and the SCTP_chunk stub itself. */
	dev_kfree_skb(chunk->skb);

	SCTP_DBG_OBJCNT_DEC(chunk);
	kmem_cache_free(sctp_chunk_cachep, chunk);
}

/* Possibly, free the chunk.  */
void sctp_chunk_free(struct sctp_chunk *chunk)
{
	/* Release our reference on the message tracker. */
	if (chunk->msg)
		sctp_datamsg_put(chunk->msg);

	sctp_chunk_put(chunk);
}

/* Grab a reference to the chunk. */
void sctp_chunk_hold(struct sctp_chunk *ch)
{
	atomic_inc(&ch->refcnt);
}

/* Release a reference to the chunk. */
void sctp_chunk_put(struct sctp_chunk *ch)
{
	if (atomic_dec_and_test(&ch->refcnt))
		sctp_chunk_destroy(ch);
}

/* Append bytes to the end of a chunk.  Will panic if chunk is not big
 * enough.
 */
void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
{
	void *target;
	void *padding;
	int chunklen = ntohs(chunk->chunk_hdr->length);
	int padlen = WORD_ROUND(chunklen) - chunklen;

	padding = skb_put(chunk->skb, padlen);
	target = skb_put(chunk->skb, len);

	memset(padding, 0, padlen);
	memcpy(target, data, len);

	/* Adjust the chunk length field.  */
	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
	chunk->chunk_end = skb_tail_pointer(chunk->skb);

	return target;
}

/* Append bytes to the end of a chunk. Returns NULL if there isn't sufficient
 * space in the chunk
 */
void *sctp_addto_chunk_fixed(struct sctp_chunk *chunk,
			     int len, const void *data)
{
	if (skb_tailroom(chunk->skb) >= len)
		return sctp_addto_chunk(chunk, len, data);
	else
		return NULL;
}

/* Append bytes from user space to the end of a chunk.  Will panic if
 * chunk is not big enough.
 * Returns a kernel err value.
 */
int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
			  struct iovec *data)
{
	__u8 *target;
	int err = 0;

	/* Make room in chunk for data.  */
	target = skb_put(chunk->skb, len);

	/* Copy data (whole iovec) into chunk */
	if ((err = memcpy_fromiovecend(target, data, off, len)))
		goto out;

	/* Adjust the chunk length field.  */
	chunk->chunk_hdr->length =
		htons(ntohs(chunk->chunk_hdr->length) + len);
	chunk->chunk_end = skb_tail_pointer(chunk->skb);

out:
	return err;
}

/* Helper function to assign a TSN if needed.  This assumes that both
 * the data_hdr and association have already been assigned.
 */
void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
{
	struct sctp_datamsg *msg;
	struct sctp_chunk *lchunk;
	struct sctp_stream *stream;
	__u16 ssn;
	__u16 sid;

	if (chunk->has_ssn)
		return;

	/* All fragments will be on the same stream */
	sid = ntohs(chunk->subh.data_hdr->stream);
	stream = &chunk->asoc->ssnmap->out;

	/* Now assign the sequence number to the entire message.
	 * All fragments must have the same stream sequence number.
	 */
	msg = chunk->msg;
	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
			ssn = 0;
		} else {
			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
				ssn = sctp_ssn_next(stream, sid);
			else
				ssn = sctp_ssn_peek(stream, sid);
		}

		lchunk->subh.data_hdr->ssn = htons(ssn);
		lchunk->has_ssn = 1;
	}
}

/* Helper function to assign a TSN if needed.  This assumes that both
 * the data_hdr and association have already been assigned.
 */
void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
{
	if (!chunk->has_tsn) {
		/* This is the last possible instant to
		 * assign a TSN.
		 */
		chunk->subh.data_hdr->tsn =
			htonl(sctp_association_get_next_tsn(chunk->asoc));
		chunk->has_tsn = 1;
	}
}

/* Create a CLOSED association to use with an incoming packet.  */
struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
					struct sctp_chunk *chunk,
					gfp_t gfp)
{
	struct sctp_association *asoc;
	struct sk_buff *skb;
	sctp_scope_t scope;
	struct sctp_af *af;

	/* Create the bare association.  */
	scope = sctp_scope(sctp_source(chunk));
	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
	if (!asoc)
		goto nodata;
	asoc->temp = 1;
	skb = chunk->skb;
	/* Create an entry for the source address of the packet.  */
	af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
	if (unlikely(!af))
		goto fail;
	af->from_skb(&asoc->c.peer_addr, skb, 1);
nodata:
	return asoc;

fail:
	sctp_association_free(asoc);
	return NULL;
}

/* Build a cookie representing asoc.
 * This INCLUDES the param header needed to put the cookie in the INIT ACK.
 */
static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
				      const struct sctp_association *asoc,
				      const struct sctp_chunk *init_chunk,
				      int *cookie_len,
				      const __u8 *raw_addrs, int addrs_len)
{
	sctp_cookie_param_t *retval;
	struct sctp_signed_cookie *cookie;
	struct scatterlist sg;
	int headersize, bodysize;
	unsigned int keylen;
	char *key;

	/* Header size is static data prior to the actual cookie, including
	 * any padding.
	 */
	headersize = sizeof(sctp_paramhdr_t) +
		     (sizeof(struct sctp_signed_cookie) -
		      sizeof(struct sctp_cookie));
	bodysize = sizeof(struct sctp_cookie)
		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;

	/* Pad out the cookie to a multiple to make the signature
	 * functions simpler to write.
	 */
	if (bodysize % SCTP_COOKIE_MULTIPLE)
		bodysize += SCTP_COOKIE_MULTIPLE
			- (bodysize % SCTP_COOKIE_MULTIPLE);
	*cookie_len = headersize + bodysize;

	/* Clear this memory since we are sending this data structure
	 * out on the network.
	 */
	retval = kzalloc(*cookie_len, GFP_ATOMIC);
	if (!retval)
		goto nodata;

	cookie = (struct sctp_signed_cookie *) retval->body;

	/* Set up the parameter header.  */
	retval->p.type = SCTP_PARAM_STATE_COOKIE;
	retval->p.length = htons(*cookie_len);

	/* Copy the cookie part of the association itself.  */
	cookie->c = asoc->c;
	/* Save the raw address list length in the cookie. */
	cookie->c.raw_addr_list_len = addrs_len;

	/* Remember PR-SCTP capability. */
	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;

	/* Save adaptation indication in the cookie. */
	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;

	/* Set an expiration time for the cookie.  */
	do_gettimeofday(&cookie->c.expiration);
	TIMEVAL_ADD(asoc->cookie_life, cookie->c.expiration);

	/* Copy the peer's init packet.  */
	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
	       ntohs(init_chunk->chunk_hdr->length));

	/* Copy the raw local address list of the association. */
	memcpy((__u8 *)&cookie->c.peer_init[0] +
	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);

	if (sctp_sk(ep->base.sk)->hmac) {
		struct hash_desc desc;

		/* Sign the message.  */
		sg_init_one(&sg, &cookie->c, bodysize);
		keylen = SCTP_SECRET_SIZE;
		key = (char *)ep->secret_key[ep->current_key];
		desc.tfm = sctp_sk(ep->base.sk)->hmac;
		desc.flags = 0;

		if (crypto_hash_setkey(desc.tfm, key, keylen) ||
		    crypto_hash_digest(&desc, &sg, bodysize, cookie->signature))
			goto free_cookie;
	}

	return retval;

free_cookie:
	kfree(retval);
nodata:
	*cookie_len = 0;
	return NULL;
}

/* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
struct sctp_association *sctp_unpack_cookie(
	const struct sctp_endpoint *ep,
	const struct sctp_association *asoc,
	struct sctp_chunk *chunk, gfp_t gfp,
	int *error, struct sctp_chunk **errp)
{
	struct sctp_association *retval = NULL;
	struct sctp_signed_cookie *cookie;
	struct sctp_cookie *bear_cookie;
	int headersize, bodysize, fixed_size;
	__u8 *digest = ep->digest;
	struct scatterlist sg;
	unsigned int keylen, len;
	char *key;
	sctp_scope_t scope;
	struct sk_buff *skb = chunk->skb;
	struct timeval tv;
	struct hash_desc desc;

	/* Header size is static data prior to the actual cookie, including
	 * any padding.
	 */
	headersize = sizeof(sctp_chunkhdr_t) +
		     (sizeof(struct sctp_signed_cookie) -
		      sizeof(struct sctp_cookie));
	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
	fixed_size = headersize + sizeof(struct sctp_cookie);

	/* Verify that the chunk looks like it even has a cookie.
	 * There must be enough room for our cookie and our peer's
	 * INIT chunk.
	 */
	len = ntohs(chunk->chunk_hdr->length);
	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
		goto malformed;

	/* Verify that the cookie has been padded out. */
	if (bodysize % SCTP_COOKIE_MULTIPLE)
		goto malformed;

	/* Process the cookie.  */
	cookie = chunk->subh.cookie_hdr;
	bear_cookie = &cookie->c;

	if (!sctp_sk(ep->base.sk)->hmac)
		goto no_hmac;

	/* Check the signature.  */
	keylen = SCTP_SECRET_SIZE;
	sg_init_one(&sg, bear_cookie, bodysize);
	key = (char *)ep->secret_key[ep->current_key];
	desc.tfm = sctp_sk(ep->base.sk)->hmac;
	desc.flags = 0;

	memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
	if (crypto_hash_setkey(desc.tfm, key, keylen) ||
	    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
		*error = -SCTP_IERROR_NOMEM;
		goto fail;
	}

	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
		/* Try the previous key. */
		key = (char *)ep->secret_key[ep->last_key];
		memset(digest, 0x00, SCTP_SIGNATURE_SIZE);
		if (crypto_hash_setkey(desc.tfm, key, keylen) ||
		    crypto_hash_digest(&desc, &sg, bodysize, digest)) {
			*error = -SCTP_IERROR_NOMEM;
			goto fail;
		}

		if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
			/* Yikes!  Still bad signature! */
			*error = -SCTP_IERROR_BAD_SIG;
			goto fail;
		}
	}

no_hmac:
	/* IG Section 2.35.2:
	 *  3) Compare the port numbers and the verification tag contained
	 *     within the COOKIE ECHO chunk to the actual port numbers and the
	 *     verification tag within the SCTP common header of the received
	 *     packet. If these values do not match the packet MUST be silently
	 *     discarded,
	 */
	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
		*error = -SCTP_IERROR_BAD_TAG;
		goto fail;
	}

	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
		*error = -SCTP_IERROR_BAD_PORTS;
		goto fail;
	}

	/* Check to see if the cookie is stale.  If there is already
	 * an association, there is no need to check cookie's expiration
	 * for init collision case of lost COOKIE ACK.
	 * If skb has been timestamped, then use the stamp, otherwise
	 * use current time.  This introduces a small possibility that
	 * that a cookie may be considered expired, but his would only slow
	 * down the new association establishment instead of every packet.
	 */
	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
		skb_get_timestamp(skb, &tv);
	else
		do_gettimeofday(&tv);

	if (!asoc && tv_lt(bear_cookie->expiration, tv)) {
		/*
		 * Section 3.3.10.3 Stale Cookie Error (3)
		 *
		 * Cause of error
		 * ---------------
		 * Stale Cookie Error:  Indicates the receipt of a valid State
		 * Cookie that has expired.
		 */
		len = ntohs(chunk->chunk_hdr->length);
		*errp = sctp_make_op_error_space(asoc, chunk, len);
		if (*errp) {
			suseconds_t usecs = (tv.tv_sec -
				bear_cookie->expiration.tv_sec) * 1000000L +
				tv.tv_usec - bear_cookie->expiration.tv_usec;
			__be32 n = htonl(usecs);

			sctp_init_cause(*errp, SCTP_ERROR_STALE_COOKIE,
					sizeof(n));
			sctp_addto_chunk(*errp, sizeof(n), &n);
			*error = -SCTP_IERROR_STALE_COOKIE;
		} else
			*error = -SCTP_IERROR_NOMEM;

		goto fail;
	}

	/* Make a new base association.  */
	scope = sctp_scope(sctp_source(chunk));
	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
	if (!retval) {
		*error = -SCTP_IERROR_NOMEM;
		goto fail;
	}

	/* Set up our peer's port number.  */
	retval->peer.port = ntohs(chunk->sctp_hdr->source);

	/* Populate the association from the cookie.  */
	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));

	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
						 GFP_ATOMIC) < 0) {
		*error = -SCTP_IERROR_NOMEM;
		goto fail;
	}

	/* Also, add the destination address. */
	if (list_empty(&retval->base.bind_addr.address_list)) {
		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
				SCTP_ADDR_SRC, GFP_ATOMIC);
	}

	retval->next_tsn = retval->c.initial_tsn;
	retval->ctsn_ack_point = retval->next_tsn - 1;
	retval->addip_serial = retval->c.initial_tsn;
	retval->adv_peer_ack_point = retval->ctsn_ack_point;
	retval->peer.prsctp_capable = retval->c.prsctp_capable;
	retval->peer.adaptation_ind = retval->c.adaptation_ind;

	/* The INIT stuff will be done by the side effects.  */
	return retval;

fail:
	if (retval)
		sctp_association_free(retval);

	return NULL;

malformed:
	/* Yikes!  The packet is either corrupt or deliberately
	 * malformed.
	 */
	*error = -SCTP_IERROR_MALFORMED;
	goto fail;
}

/********************************************************************
 * 3rd Level Abstractions
 ********************************************************************/

struct __sctp_missing {
	__be32 num_missing;
	__be16 type;
}  __packed;

/*
 * Report a missing mandatory parameter.
 */
static int sctp_process_missing_param(const struct sctp_association *asoc,
				      sctp_param_t paramtype,
				      struct sctp_chunk *chunk,
				      struct sctp_chunk **errp)
{
	struct __sctp_missing report;
	__u16 len;

	len = WORD_ROUND(sizeof(report));

	/* Make an ERROR chunk, preparing enough room for
	 * returning multiple unknown parameters.
	 */
	if (!*errp)
		*errp = sctp_make_op_error_space(asoc, chunk, len);

	if (*errp) {
		report.num_missing = htonl(1);
		report.type = paramtype;
		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
				sizeof(report));
		sctp_addto_chunk(*errp, sizeof(report), &report);
	}

	/* Stop processing this chunk. */
	return 0;
}

/* Report an Invalid Mandatory Parameter.  */
static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
				      struct sctp_chunk *chunk,
				      struct sctp_chunk **errp)
{
	/* Invalid Mandatory Parameter Error has no payload. */

	if (!*errp)
		*errp = sctp_make_op_error_space(asoc, chunk, 0);

	if (*errp)
		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);

	/* Stop processing this chunk. */
	return 0;
}

static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
					struct sctp_paramhdr *param,
					const struct sctp_chunk *chunk,
					struct sctp_chunk **errp)
{
	/* This is a fatal error.  Any accumulated non-fatal errors are
	 * not reported.
	 */
	if (*errp)
		sctp_chunk_free(*errp);

	/* Create an error chunk and fill it in with our payload. */
	*errp = sctp_make_violation_paramlen(asoc, chunk, param);

	return 0;
}


/* Do not attempt to handle the HOST_NAME parm.  However, do
 * send back an indicator to the peer.
 */
static int sctp_process_hn_param(const struct sctp_association *asoc,
				 union sctp_params param,
				 struct sctp_chunk *chunk,
				 struct sctp_chunk **errp)
{
	__u16 len = ntohs(param.p->length);

	/* Processing of the HOST_NAME parameter will generate an
	 * ABORT.  If we've accumulated any non-fatal errors, they
	 * would be unrecognized parameters and we should not include
	 * them in the ABORT.
	 */
	if (*errp)
		sctp_chunk_free(*errp);

	*errp = sctp_make_op_error_space(asoc, chunk, len);

	if (*errp) {
		sctp_init_cause(*errp, SCTP_ERROR_DNS_FAILED, len);
		sctp_addto_chunk(*errp, len, param.v);
	}

	/* Stop processing this chunk. */
	return 0;
}

static int sctp_verify_ext_param(union sctp_params param)
{
	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
	int have_auth = 0;
	int have_asconf = 0;
	int i;

	for (i = 0; i < num_ext; i++) {
		switch (param.ext->chunks[i]) {
		    case SCTP_CID_AUTH:
			    have_auth = 1;
			    break;
		    case SCTP_CID_ASCONF:
		    case SCTP_CID_ASCONF_ACK:
			    have_asconf = 1;
			    break;
		}
	}

	/* ADD-IP Security: The draft requires us to ABORT or ignore the
	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
	 * only if ADD-IP is turned on and we are not backward-compatible
	 * mode.
	 */
	if (sctp_addip_noauth)
		return 1;

	if (sctp_addip_enable && !have_auth && have_asconf)
		return 0;

	return 1;
}

static void sctp_process_ext_param(struct sctp_association *asoc,
				    union sctp_params param)
{
	__u16 num_ext = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
	int i;

	for (i = 0; i < num_ext; i++) {
		switch (param.ext->chunks[i]) {
		    case SCTP_CID_FWD_TSN:
			    if (sctp_prsctp_enable &&
				!asoc->peer.prsctp_capable)
				    asoc->peer.prsctp_capable = 1;
			    break;
		    case SCTP_CID_AUTH:
			    /* if the peer reports AUTH, assume that he
			     * supports AUTH.
			     */
			    if (sctp_auth_enable)
				    asoc->peer.auth_capable = 1;
			    break;
		    case SCTP_CID_ASCONF:
		    case SCTP_CID_ASCONF_ACK:
			    if (sctp_addip_enable)
				    asoc->peer.asconf_capable = 1;
			    break;
		    default:
			    break;
		}
	}
}

/* RFC 3.2.1 & the Implementers Guide 2.2.
 *
 * The Parameter Types are encoded such that the
 * highest-order two bits specify the action that must be
 * taken if the processing endpoint does not recognize the
 * Parameter Type.
 *
 * 00 - Stop processing this parameter; do not process any further
 * 	parameters within this chunk
 *
 * 01 - Stop processing this parameter, do not process any further
 *	parameters within this chunk, and report the unrecognized
 *	parameter in an 'Unrecognized Parameter' ERROR chunk.
 *
 * 10 - Skip this parameter and continue processing.
 *
 * 11 - Skip this parameter and continue processing but
 *	report the unrecognized parameter in an
 *	'Unrecognized Parameter' ERROR chunk.
 *
 * Return value:
 * 	SCTP_IERROR_NO_ERROR - continue with the chunk
 * 	SCTP_IERROR_ERROR    - stop and report an error.
 * 	SCTP_IERROR_NOMEME   - out of memory.
 */
static sctp_ierror_t sctp_process_unk_param(const struct sctp_association *asoc,
					    union sctp_params param,
					    struct sctp_chunk *chunk,
					    struct sctp_chunk **errp)
{
	int retval = SCTP_IERROR_NO_ERROR;

	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
	case SCTP_PARAM_ACTION_DISCARD:
		retval =  SCTP_IERROR_ERROR;
		break;
	case SCTP_PARAM_ACTION_SKIP:
		break;
	case SCTP_PARAM_ACTION_DISCARD_ERR:
		retval =  SCTP_IERROR_ERROR;
		/* Fall through */
	case SCTP_PARAM_ACTION_SKIP_ERR:
		/* Make an ERROR chunk, preparing enough room for
		 * returning multiple unknown parameters.
		 */
		if (NULL == *errp)
			*errp = sctp_make_op_error_fixed(asoc, chunk);

		if (*errp) {
			if (!sctp_init_cause_fixed(*errp, SCTP_ERROR_UNKNOWN_PARAM,
					WORD_ROUND(ntohs(param.p->length))))
				sctp_addto_chunk_fixed(*errp,
						WORD_ROUND(ntohs(param.p->length)),
						param.v);
		} else {
			/* If there is no memory for generating the ERROR
			 * report as specified, an ABORT will be triggered
			 * to the peer and the association won't be
			 * established.
			 */
			retval = SCTP_IERROR_NOMEM;
		}
		break;
	default:
		break;
	}

	return retval;
}

/* Verify variable length parameters
 * Return values:
 * 	SCTP_IERROR_ABORT - trigger an ABORT
 * 	SCTP_IERROR_NOMEM - out of memory (abort)
 *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
 * 	SCTP_IERROR_NO_ERROR - continue with the chunk
 */
static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
					union sctp_params param,
					sctp_cid_t cid,
					struct sctp_chunk *chunk,
					struct sctp_chunk **err_chunk)
{
	struct sctp_hmac_algo_param *hmacs;
	int retval = SCTP_IERROR_NO_ERROR;
	__u16 n_elt, id = 0;
	int i;

	/* FIXME - This routine is not looking at each parameter per the
	 * chunk type, i.e., unrecognized parameters should be further
	 * identified based on the chunk id.
	 */

	switch (param.p->type) {
	case SCTP_PARAM_IPV4_ADDRESS:
	case SCTP_PARAM_IPV6_ADDRESS:
	case SCTP_PARAM_COOKIE_PRESERVATIVE:
	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
	case SCTP_PARAM_STATE_COOKIE:
	case SCTP_PARAM_HEARTBEAT_INFO:
	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
	case SCTP_PARAM_ECN_CAPABLE:
	case SCTP_PARAM_ADAPTATION_LAYER_IND:
		break;

	case SCTP_PARAM_SUPPORTED_EXT:
		if (!sctp_verify_ext_param(param))
			return SCTP_IERROR_ABORT;
		break;

	case SCTP_PARAM_SET_PRIMARY:
		if (sctp_addip_enable)
			break;
		goto fallthrough;

	case SCTP_PARAM_HOST_NAME_ADDRESS:
		/* Tell the peer, we won't support this param.  */
		sctp_process_hn_param(asoc, param, chunk, err_chunk);
		retval = SCTP_IERROR_ABORT;
		break;

	case SCTP_PARAM_FWD_TSN_SUPPORT:
		if (sctp_prsctp_enable)
			break;
		goto fallthrough;

	case SCTP_PARAM_RANDOM:
		if (!sctp_auth_enable)
			goto fallthrough;

		/* SCTP-AUTH: Secion 6.1
		 * If the random number is not 32 byte long the association
		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
		 * cause 'Protocol Violation'.
		 */
		if (SCTP_AUTH_RANDOM_LENGTH !=
			ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) {
			sctp_process_inv_paramlength(asoc, param.p,
							chunk, err_chunk);
			retval = SCTP_IERROR_ABORT;
		}
		break;

	case SCTP_PARAM_CHUNKS:
		if (!sctp_auth_enable)
			goto fallthrough;

		/* SCTP-AUTH: Section 3.2
		 * The CHUNKS parameter MUST be included once in the INIT or
		 *  INIT-ACK chunk if the sender wants to receive authenticated
		 *  chunks.  Its maximum length is 260 bytes.
		 */
		if (260 < ntohs(param.p->length)) {
			sctp_process_inv_paramlength(asoc, param.p,
						     chunk, err_chunk);
			retval = SCTP_IERROR_ABORT;
		}
		break;

	case SCTP_PARAM_HMAC_ALGO:
		if (!sctp_auth_enable)
			goto fallthrough;

		hmacs = (struct sctp_hmac_algo_param *)param.p;
		n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;

		/* SCTP-AUTH: Section 6.1
		 * The HMAC algorithm based on SHA-1 MUST be supported and
		 * included in the HMAC-ALGO parameter.
		 */
		for (i = 0; i < n_elt; i++) {
			id = ntohs(hmacs->hmac_ids[i]);

			if (id == SCTP_AUTH_HMAC_ID_SHA1)
				break;
		}

		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
			sctp_process_inv_paramlength(asoc, param.p, chunk,
						     err_chunk);
			retval = SCTP_IERROR_ABORT;
		}
		break;
fallthrough:
	default:
		SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",
				ntohs(param.p->type), cid);
		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
		break;
	}
	return retval;
}

/* Verify the INIT packet before we process it.  */
int sctp_verify_init(const struct sctp_association *asoc,
		     sctp_cid_t cid,
		     sctp_init_chunk_t *peer_init,
		     struct sctp_chunk *chunk,
		     struct sctp_chunk **errp)
{
	union sctp_params param;
	int has_cookie = 0;
	int result;

	/* Verify stream values are non-zero. */
	if ((0 == peer_init->init_hdr.num_outbound_streams) ||
	    (0 == peer_init->init_hdr.num_inbound_streams) ||
	    (0 == peer_init->init_hdr.init_tag) ||
	    (SCTP_DEFAULT_MINWINDOW > ntohl(peer_init->init_hdr.a_rwnd))) {

		return sctp_process_inv_mandatory(asoc, chunk, errp);
	}

	/* Check for missing mandatory parameters.  */
	sctp_walk_params(param, peer_init, init_hdr.params) {

		if (SCTP_PARAM_STATE_COOKIE == param.p->type)
			has_cookie = 1;

	} /* for (loop through all parameters) */

	/* There is a possibility that a parameter length was bad and
	 * in that case we would have stoped walking the parameters.
	 * The current param.p would point at the bad one.
	 * Current consensus on the mailing list is to generate a PROTOCOL
	 * VIOLATION error.  We build the ERROR chunk here and let the normal
	 * error handling code build and send the packet.
	 */
	if (param.v != (void*)chunk->chunk_end)
		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);

	/* The only missing mandatory param possible today is
	 * the state cookie for an INIT-ACK chunk.
	 */
	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
						  chunk, errp);

	/* Verify all the variable length parameters */
	sctp_walk_params(param, peer_init, init_hdr.params) {

		result = sctp_verify_param(asoc, param, cid, chunk, errp);
		switch (result) {
		    case SCTP_IERROR_ABORT:
		    case SCTP_IERROR_NOMEM:
				return 0;
		    case SCTP_IERROR_ERROR:
				return 1;
		    case SCTP_IERROR_NO_ERROR:
		    default:
				break;
		}

	} /* for (loop through all parameters) */

	return 1;
}

/* Unpack the parameters in an INIT packet into an association.
 * Returns 0 on failure, else success.
 * FIXME:  This is an association method.
 */
int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
		      const union sctp_addr *peer_addr,
		      sctp_init_chunk_t *peer_init, gfp_t gfp)
{
	union sctp_params param;
	struct sctp_transport *transport;
	struct list_head *pos, *temp;
	struct sctp_af *af;
	union sctp_addr addr;
	char *cookie;
	int src_match = 0;

	/* We must include the address that the INIT packet came from.
	 * This is the only address that matters for an INIT packet.
	 * When processing a COOKIE ECHO, we retrieve the from address
	 * of the INIT from the cookie.
	 */

	/* This implementation defaults to making the first transport
	 * added as the primary transport.  The source address seems to
	 * be a a better choice than any of the embedded addresses.
	 */
	if(!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
		goto nomem;

	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
		src_match = 1;

	/* Process the initialization parameters.  */
	sctp_walk_params(param, peer_init, init_hdr.params) {
		if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
			af = sctp_get_af_specific(param_type2af(param.p->type));
			af->from_addr_param(&addr, param.addr,
					    chunk->sctp_hdr->source, 0);
			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
				src_match = 1;
		}

		if (!sctp_process_param(asoc, param, peer_addr, gfp))
			goto clean_up;
	}

	/* source address of chunk may not match any valid address */
	if (!src_match)
		goto clean_up;

	/* AUTH: After processing the parameters, make sure that we
	 * have all the required info to potentially do authentications.
	 */
	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
					!asoc->peer.peer_hmacs))
		asoc->peer.auth_capable = 0;

	/* In a non-backward compatible mode, if the peer claims
	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
	 * that we MUST ABORT the association. Section 6.  The section
	 * also give us an option to silently ignore the packet, which
	 * is what we'll do here.
	 */
	if (!sctp_addip_noauth &&
	     (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
						  SCTP_PARAM_DEL_IP |
						  SCTP_PARAM_SET_PRIMARY);
		asoc->peer.asconf_capable = 0;
		goto clean_up;
	}

	/* Walk list of transports, removing transports in the UNKNOWN state. */
	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
		transport = list_entry(pos, struct sctp_transport, transports);
		if (transport->state == SCTP_UNKNOWN) {
			sctp_assoc_rm_peer(asoc, transport);
		}
	}

	/* The fixed INIT headers are always in network byte
	 * order.
	 */
	asoc->peer.i.init_tag =
		ntohl(peer_init->init_hdr.init_tag);
	asoc->peer.i.a_rwnd =
		ntohl(peer_init->init_hdr.a_rwnd);
	asoc->peer.i.num_outbound_streams =
		ntohs(peer_init->init_hdr.num_outbound_streams);
	asoc->peer.i.num_inbound_streams =
		ntohs(peer_init->init_hdr.num_inbound_streams);
	asoc->peer.i.initial_tsn =
		ntohl(peer_init->init_hdr.initial_tsn);

	/* Apply the upper bounds for output streams based on peer's
	 * number of inbound streams.
	 */
	if (asoc->c.sinit_num_ostreams  >
	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
		asoc->c.sinit_num_ostreams =
			ntohs(peer_init->init_hdr.num_inbound_streams);
	}

	if (asoc->c.sinit_max_instreams >
	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
		asoc->c.sinit_max_instreams =
			ntohs(peer_init->init_hdr.num_outbound_streams);
	}

	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
	asoc->c.peer_vtag = asoc->peer.i.init_tag;

	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
	asoc->peer.rwnd = asoc->peer.i.a_rwnd;

	/* Copy cookie in case we need to resend COOKIE-ECHO. */
	cookie = asoc->peer.cookie;
	if (cookie) {
		asoc->peer.cookie = kmemdup(cookie, asoc->peer.cookie_len, gfp);
		if (!asoc->peer.cookie)
			goto clean_up;
	}

	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
	 * high (for example, implementations MAY use the size of the receiver
	 * advertised window).
	 */
	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
			transports) {
		transport->ssthresh = asoc->peer.i.a_rwnd;
	}

	/* Set up the TSN tracking pieces.  */
	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
				asoc->peer.i.initial_tsn, gfp))
		goto clean_up;

	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
	 *
	 * The stream sequence number in all the streams shall start
	 * from 0 when the association is established.  Also, when the
	 * stream sequence number reaches the value 65535 the next
	 * stream sequence number shall be set to 0.
	 */

	/* Allocate storage for the negotiated streams if it is not a temporary
	 * association.
	 */
	if (!asoc->temp) {
		int error;

		asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
					       asoc->c.sinit_num_ostreams, gfp);
		if (!asoc->ssnmap)
			goto clean_up;

		error = sctp_assoc_set_id(asoc, gfp);
		if (error)
			goto clean_up;
	}

	/* ADDIP Section 4.1 ASCONF Chunk Procedures
	 *
	 * When an endpoint has an ASCONF signaled change to be sent to the
	 * remote endpoint it should do the following:
	 * ...
	 * A2) A serial number should be assigned to the Chunk. The serial
	 * number should be a monotonically increasing number. All serial
	 * numbers are defined to be initialized at the start of the
	 * association to the same value as the Initial TSN.
	 */
	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
	return 1;

clean_up:
	/* Release the transport structures. */
	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
		transport = list_entry(pos, struct sctp_transport, transports);
		if (transport->state != SCTP_ACTIVE)
			sctp_assoc_rm_peer(asoc, transport);
	}

nomem:
	return 0;
}


/* Update asoc with the option described in param.
 *
 * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
 *
 * asoc is the association to update.
 * param is the variable length parameter to use for update.
 * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
 * If the current packet is an INIT we want to minimize the amount of
 * work we do.  In particular, we should not build transport
 * structures for the addresses.
 */
static int sctp_process_param(struct sctp_association *asoc,
			      union sctp_params param,
			      const union sctp_addr *peer_addr,
			      gfp_t gfp)
{
	union sctp_addr addr;
	int i;
	__u16 sat;
	int retval = 1;
	sctp_scope_t scope;
	time_t stale;
	struct sctp_af *af;
	union sctp_addr_param *addr_param;
	struct sctp_transport *t;

	/* We maintain all INIT parameters in network byte order all the
	 * time.  This allows us to not worry about whether the parameters
	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
	 */
	switch (param.p->type) {
	case SCTP_PARAM_IPV6_ADDRESS:
		if (PF_INET6 != asoc->base.sk->sk_family)
			break;
		goto do_addr_param;

	case SCTP_PARAM_IPV4_ADDRESS:
		/* v4 addresses are not allowed on v6-only socket */
		if (ipv6_only_sock(asoc->base.sk))
			break;
do_addr_param:
		af = sctp_get_af_specific(param_type2af(param.p->type));
		af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
		scope = sctp_scope(peer_addr);
		if (sctp_in_scope(&addr, scope))
			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
				return 0;
		break;

	case SCTP_PARAM_COOKIE_PRESERVATIVE:
		if (!sctp_cookie_preserve_enable)
			break;

		stale = ntohl(param.life->lifespan_increment);

		/* Suggested Cookie Life span increment's unit is msec,
		 * (1/1000sec).
		 */
		asoc->cookie_life.tv_sec += stale / 1000;
		asoc->cookie_life.tv_usec += (stale % 1000) * 1000;
		break;

	case SCTP_PARAM_HOST_NAME_ADDRESS:
		SCTP_DEBUG_PRINTK("unimplemented SCTP_HOST_NAME_ADDRESS\n");
		break;

	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
		/* Turn off the default values first so we'll know which
		 * ones are really set by the peer.
		 */
		asoc->peer.ipv4_address = 0;
		asoc->peer.ipv6_address = 0;

		/* Assume that peer supports the address family
		 * by which it sends a packet.
		 */
		if (peer_addr->sa.sa_family == AF_INET6)
			asoc->peer.ipv6_address = 1;
		else if (peer_addr->sa.sa_family == AF_INET)
			asoc->peer.ipv4_address = 1;

		/* Cycle through address types; avoid divide by 0. */
		sat = ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
		if (sat)
			sat /= sizeof(__u16);

		for (i = 0; i < sat; ++i) {
			switch (param.sat->types[i]) {
			case SCTP_PARAM_IPV4_ADDRESS:
				asoc->peer.ipv4_address = 1;
				break;

			case SCTP_PARAM_IPV6_ADDRESS:
				if (PF_INET6 == asoc->base.sk->sk_family)
					asoc->peer.ipv6_address = 1;
				break;

			case SCTP_PARAM_HOST_NAME_ADDRESS:
				asoc->peer.hostname_address = 1;
				break;

			default: /* Just ignore anything else.  */
				break;
			}
		}
		break;

	case SCTP_PARAM_STATE_COOKIE:
		asoc->peer.cookie_len =
			ntohs(param.p->length) - sizeof(sctp_paramhdr_t);
		asoc->peer.cookie = param.cookie->body;
		break;

	case SCTP_PARAM_HEARTBEAT_INFO:
		/* Would be odd to receive, but it causes no problems. */
		break;

	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
		/* Rejected during verify stage. */
		break;

	case SCTP_PARAM_ECN_CAPABLE:
		asoc->peer.ecn_capable = 1;
		break;

	case SCTP_PARAM_ADAPTATION_LAYER_IND:
		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
		break;

	case SCTP_PARAM_SET_PRIMARY:
		if (!sctp_addip_enable)
			goto fall_through;

		addr_param = param.v + sizeof(sctp_addip_param_t);

		af = sctp_get_af_specific(param_type2af(param.p->type));
		af->from_addr_param(&addr, addr_param,
				    htons(asoc->peer.port), 0);

		/* if the address is invalid, we can't process it.
		 * XXX: see spec for what to do.
		 */
		if (!af->addr_valid(&addr, NULL, NULL))
			break;

		t = sctp_assoc_lookup_paddr(asoc, &addr);
		if (!t)
			break;

		sctp_assoc_set_primary(asoc, t);
		break;

	case SCTP_PARAM_SUPPORTED_EXT:
		sctp_process_ext_param(asoc, param);
		break;

	case SCTP_PARAM_FWD_TSN_SUPPORT:
		if (sctp_prsctp_enable) {
			asoc->peer.prsctp_capable = 1;
			break;
		}
		/* Fall Through */
		goto fall_through;

	case SCTP_PARAM_RANDOM:
		if (!sctp_auth_enable)
			goto fall_through;

		/* Save peer's random parameter */
		asoc->peer.peer_random = kmemdup(param.p,
					    ntohs(param.p->length), gfp);
		if (!asoc->peer.peer_random) {
			retval = 0;
			break;
		}
		break;

	case SCTP_PARAM_HMAC_ALGO:
		if (!sctp_auth_enable)
			goto fall_through;

		/* Save peer's HMAC list */
		asoc->peer.peer_hmacs = kmemdup(param.p,
					    ntohs(param.p->length), gfp);
		if (!asoc->peer.peer_hmacs) {
			retval = 0;
			break;
		}

		/* Set the default HMAC the peer requested*/
		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
		break;

	case SCTP_PARAM_CHUNKS:
		if (!sctp_auth_enable)
			goto fall_through;

		asoc->peer.peer_chunks = kmemdup(param.p,
					    ntohs(param.p->length), gfp);
		if (!asoc->peer.peer_chunks)
			retval = 0;
		break;
fall_through:
	default:
		/* Any unrecognized parameters should have been caught
		 * and handled by sctp_verify_param() which should be
		 * called prior to this routine.  Simply log the error
		 * here.
		 */
		SCTP_DEBUG_PRINTK("Ignoring param: %d for association %p.\n",
				  ntohs(param.p->type), asoc);
		break;
	}

	return retval;
}

/* Select a new verification tag.  */
__u32 sctp_generate_tag(const struct sctp_endpoint *ep)
{
	/* I believe that this random number generator complies with RFC1750.
	 * A tag of 0 is reserved for special cases (e.g. INIT).
	 */
	__u32 x;

	do {
		get_random_bytes(&x, sizeof(__u32));
	} while (x == 0);

	return x;
}

/* Select an initial TSN to send during startup.  */
__u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
{
	__u32 retval;

	get_random_bytes(&retval, sizeof(__u32));
	return retval;
}

/*
 * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
 *      0                   1                   2                   3
 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                       Serial Number                           |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                    Address Parameter                          |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                     ASCONF Parameter #1                       |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     \                                                               \
 *     /                             ....                              /
 *     \                                                               \
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                     ASCONF Parameter #N                       |
 *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * Address Parameter and other parameter will not be wrapped in this function
 */
static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
					   union sctp_addr *addr,
					   int vparam_len)
{
	sctp_addiphdr_t asconf;
	struct sctp_chunk *retval;
	int length = sizeof(asconf) + vparam_len;
	union sctp_addr_param addrparam;
	int addrlen;
	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);

	addrlen = af->to_addr_param(addr, &addrparam);
	if (!addrlen)
		return NULL;
	length += addrlen;

	/* Create the chunk.  */
	retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF, 0, length);
	if (!retval)
		return NULL;

	asconf.serial = htonl(asoc->addip_serial++);

	retval->subh.addip_hdr =
		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
	retval->param_hdr.v =
		sctp_addto_chunk(retval, addrlen, &addrparam);

	return retval;
}

/* ADDIP
 * 3.2.1 Add IP Address
 * 	0                   1                   2                   3
 * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |        Type = 0xC001          |    Length = Variable          |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |               ASCONF-Request Correlation ID                   |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                       Address Parameter                       |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * 3.2.2 Delete IP Address
 * 	0                   1                   2                   3
 * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |        Type = 0xC002          |    Length = Variable          |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |               ASCONF-Request Correlation ID                   |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                       Address Parameter                       |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 */
struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
					      union sctp_addr	      *laddr,
					      struct sockaddr	      *addrs,
					      int		      addrcnt,
					      __be16		      flags)
{
	sctp_addip_param_t	param;
	struct sctp_chunk	*retval;
	union sctp_addr_param	addr_param;
	union sctp_addr		*addr;
	void			*addr_buf;
	struct sctp_af		*af;
	int			paramlen = sizeof(param);
	int			addr_param_len = 0;
	int 			totallen = 0;
	int 			i;
	int			del_pickup = 0;

	/* Get total length of all the address parameters. */
	addr_buf = addrs;
	for (i = 0; i < addrcnt; i++) {
		addr = addr_buf;
		af = sctp_get_af_specific(addr->v4.sin_family);
		addr_param_len = af->to_addr_param(addr, &addr_param);

		totallen += paramlen;
		totallen += addr_param_len;

		addr_buf += af->sockaddr_len;
		if (asoc->asconf_addr_del_pending && !del_pickup) {
			/* reuse the parameter length from the same scope one */
			totallen += paramlen;
			totallen += addr_param_len;
			del_pickup = 1;
			SCTP_DEBUG_PRINTK("mkasconf_update_ip: picked same-scope del_pending addr, totallen for all addresses is %d\n", totallen);
		}
	}

	/* Create an asconf chunk with the required length. */
	retval = sctp_make_asconf(asoc, laddr, totallen);
	if (!retval)
		return NULL;

	/* Add the address parameters to the asconf chunk. */
	addr_buf = addrs;
	for (i = 0; i < addrcnt; i++) {
		addr = addr_buf;
		af = sctp_get_af_specific(addr->v4.sin_family);
		addr_param_len = af->to_addr_param(addr, &addr_param);
		param.param_hdr.type = flags;
		param.param_hdr.length = htons(paramlen + addr_param_len);
		param.crr_id = i;

		sctp_addto_chunk(retval, paramlen, &param);
		sctp_addto_chunk(retval, addr_param_len, &addr_param);

		addr_buf += af->sockaddr_len;
	}
	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
		addr = asoc->asconf_addr_del_pending;
		af = sctp_get_af_specific(addr->v4.sin_family);
		addr_param_len = af->to_addr_param(addr, &addr_param);
		param.param_hdr.type = SCTP_PARAM_DEL_IP;
		param.param_hdr.length = htons(paramlen + addr_param_len);
		param.crr_id = i;

		sctp_addto_chunk(retval, paramlen, &param);
		sctp_addto_chunk(retval, addr_param_len, &addr_param);
	}
	return retval;
}

/* ADDIP
 * 3.2.4 Set Primary IP Address
 *	0                   1                   2                   3
 *	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |        Type =0xC004           |    Length = Variable          |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |               ASCONF-Request Correlation ID                   |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                       Address Parameter                       |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * Create an ASCONF chunk with Set Primary IP address parameter.
 */
struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
					     union sctp_addr *addr)
{
	sctp_addip_param_t	param;
	struct sctp_chunk 	*retval;
	int 			len = sizeof(param);
	union sctp_addr_param	addrparam;
	int			addrlen;
	struct sctp_af		*af = sctp_get_af_specific(addr->v4.sin_family);

	addrlen = af->to_addr_param(addr, &addrparam);
	if (!addrlen)
		return NULL;
	len += addrlen;

	/* Create the chunk and make asconf header. */
	retval = sctp_make_asconf(asoc, addr, len);
	if (!retval)
		return NULL;

	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
	param.param_hdr.length = htons(len);
	param.crr_id = 0;

	sctp_addto_chunk(retval, sizeof(param), &param);
	sctp_addto_chunk(retval, addrlen, &addrparam);

	return retval;
}

/* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
 *      0                   1                   2                   3
 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                       Serial Number                           |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                 ASCONF Parameter Response#1                   |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     \                                                               \
 *     /                             ....                              /
 *     \                                                               \
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *     |                 ASCONF Parameter Response#N                   |
 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * Create an ASCONF_ACK chunk with enough space for the parameter responses.
 */
static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
					       __u32 serial, int vparam_len)
{
	sctp_addiphdr_t		asconf;
	struct sctp_chunk	*retval;
	int			length = sizeof(asconf) + vparam_len;

	/* Create the chunk.  */
	retval = sctp_make_chunk(asoc, SCTP_CID_ASCONF_ACK, 0, length);
	if (!retval)
		return NULL;

	asconf.serial = htonl(serial);

	retval->subh.addip_hdr =
		sctp_addto_chunk(retval, sizeof(asconf), &asconf);

	return retval;
}

/* Add response parameters to an ASCONF_ACK chunk. */
static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
			      __be16 err_code, sctp_addip_param_t *asconf_param)
{
	sctp_addip_param_t 	ack_param;
	sctp_errhdr_t		err_param;
	int			asconf_param_len = 0;
	int			err_param_len = 0;
	__be16			response_type;

	if (SCTP_ERROR_NO_ERROR == err_code) {
		response_type = SCTP_PARAM_SUCCESS_REPORT;
	} else {
		response_type = SCTP_PARAM_ERR_CAUSE;
		err_param_len = sizeof(err_param);
		if (asconf_param)
			asconf_param_len =
				 ntohs(asconf_param->param_hdr.length);
	}

	/* Add Success Indication or Error Cause Indication parameter. */
	ack_param.param_hdr.type = response_type;
	ack_param.param_hdr.length = htons(sizeof(ack_param) +
					   err_param_len +
					   asconf_param_len);
	ack_param.crr_id = crr_id;
	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);

	if (SCTP_ERROR_NO_ERROR == err_code)
		return;

	/* Add Error Cause parameter. */
	err_param.cause = err_code;
	err_param.length = htons(err_param_len + asconf_param_len);
	sctp_addto_chunk(chunk, err_param_len, &err_param);

	/* Add the failed TLV copied from ASCONF chunk. */
	if (asconf_param)
		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
}

/* Process a asconf parameter. */
static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
				       struct sctp_chunk *asconf,
				       sctp_addip_param_t *asconf_param)
{
	struct sctp_transport *peer;
	struct sctp_af *af;
	union sctp_addr	addr;
	union sctp_addr_param *addr_param;

	addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);

	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
		return SCTP_ERROR_UNKNOWN_PARAM;

	switch (addr_param->p.type) {
	case SCTP_PARAM_IPV6_ADDRESS:
		if (!asoc->peer.ipv6_address)
			return SCTP_ERROR_DNS_FAILED;
		break;
	case SCTP_PARAM_IPV4_ADDRESS:
		if (!asoc->peer.ipv4_address)
			return SCTP_ERROR_DNS_FAILED;
		break;
	default:
		return SCTP_ERROR_DNS_FAILED;
	}

	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
	if (unlikely(!af))
		return SCTP_ERROR_DNS_FAILED;

	af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);

	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
	 * or multicast address.
	 * (note: wildcard is permitted and requires special handling so
	 *  make sure we check for that)
	 */
	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
		return SCTP_ERROR_DNS_FAILED;

	switch (asconf_param->param_hdr.type) {
	case SCTP_PARAM_ADD_IP:
		/* Section 4.2.1:
		 * If the address 0.0.0.0 or ::0 is provided, the source
		 * address of the packet MUST be added.
		 */
		if (af->is_any(&addr))
			memcpy(&addr, &asconf->source, sizeof(addr));

		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
		 * request and does not have the local resources to add this
		 * new address to the association, it MUST return an Error
		 * Cause TLV set to the new error code 'Operation Refused
		 * Due to Resource Shortage'.
		 */

		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
		if (!peer)
			return SCTP_ERROR_RSRC_LOW;

		/* Start the heartbeat timer. */
		if (!mod_timer(&peer->hb_timer, sctp_transport_timeout(peer)))
			sctp_transport_hold(peer);
		asoc->new_transport = peer;
		break;
	case SCTP_PARAM_DEL_IP:
		/* ADDIP 4.3 D7) If a request is received to delete the
		 * last remaining IP address of a peer endpoint, the receiver
		 * MUST send an Error Cause TLV with the error cause set to the
		 * new error code 'Request to Delete Last Remaining IP Address'.
		 */
		if (asoc->peer.transport_count == 1)
			return SCTP_ERROR_DEL_LAST_IP;

		/* ADDIP 4.3 D8) If a request is received to delete an IP
		 * address which is also the source address of the IP packet
		 * which contained the ASCONF chunk, the receiver MUST reject
		 * this request. To reject the request the receiver MUST send
		 * an Error Cause TLV set to the new error code 'Request to
		 * Delete Source IP Address'
		 */
		if (sctp_cmp_addr_exact(&asconf->source, &addr))
			return SCTP_ERROR_DEL_SRC_IP;

		/* Section 4.2.2
		 * If the address 0.0.0.0 or ::0 is provided, all
		 * addresses of the peer except	the source address of the
		 * packet MUST be deleted.
		 */
		if (af->is_any(&addr)) {
			sctp_assoc_set_primary(asoc, asconf->transport);
			sctp_assoc_del_nonprimary_peers(asoc,
							asconf->transport);
		} else
			sctp_assoc_del_peer(asoc, &addr);
		break;
	case SCTP_PARAM_SET_PRIMARY:
		/* ADDIP Section 4.2.4
		 * If the address 0.0.0.0 or ::0 is provided, the receiver
		 * MAY mark the source address of the packet as its
		 * primary.
		 */
		if (af->is_any(&addr))
			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));

		peer = sctp_assoc_lookup_paddr(asoc, &addr);
		if (!peer)
			return SCTP_ERROR_DNS_FAILED;

		sctp_assoc_set_primary(asoc, peer);
		break;
	}

	return SCTP_ERROR_NO_ERROR;
}

/* Verify the ASCONF packet before we process it.  */
int sctp_verify_asconf(const struct sctp_association *asoc,
		       struct sctp_paramhdr *param_hdr, void *chunk_end,
		       struct sctp_paramhdr **errp) {
	sctp_addip_param_t *asconf_param;
	union sctp_params param;
	int length, plen;

	param.v = (sctp_paramhdr_t *) param_hdr;
	while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
		length = ntohs(param.p->length);
		*errp = param.p;

		if (param.v > chunk_end - length ||
		    length < sizeof(sctp_paramhdr_t))
			return 0;

		switch (param.p->type) {
		case SCTP_PARAM_ADD_IP:
		case SCTP_PARAM_DEL_IP:
		case SCTP_PARAM_SET_PRIMARY:
			asconf_param = (sctp_addip_param_t *)param.v;
			plen = ntohs(asconf_param->param_hdr.length);
			if (plen < sizeof(sctp_addip_param_t) +
			    sizeof(sctp_paramhdr_t))
				return 0;
			break;
		case SCTP_PARAM_SUCCESS_REPORT:
		case SCTP_PARAM_ADAPTATION_LAYER_IND:
			if (length != sizeof(sctp_addip_param_t))
				return 0;

			break;
		default:
			break;
		}

		param.v += WORD_ROUND(length);
	}

	if (param.v != chunk_end)
		return 0;

	return 1;
}

/* Process an incoming ASCONF chunk with the next expected serial no. and
 * return an ASCONF_ACK chunk to be sent in response.
 */
struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
				       struct sctp_chunk *asconf)
{
	sctp_addiphdr_t		*hdr;
	union sctp_addr_param	*addr_param;
	sctp_addip_param_t	*asconf_param;
	struct sctp_chunk	*asconf_ack;

	__be16	err_code;
	int	length = 0;
	int	chunk_len;
	__u32	serial;
	int	all_param_pass = 1;

	chunk_len = ntohs(asconf->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
	hdr = (sctp_addiphdr_t *)asconf->skb->data;
	serial = ntohl(hdr->serial);

	/* Skip the addiphdr and store a pointer to address parameter.  */
	length = sizeof(sctp_addiphdr_t);
	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
	chunk_len -= length;

	/* Skip the address parameter and store a pointer to the first
	 * asconf parameter.
	 */
	length = ntohs(addr_param->p.length);
	asconf_param = (void *)addr_param + length;
	chunk_len -= length;

	/* create an ASCONF_ACK chunk.
	 * Based on the definitions of parameters, we know that the size of
	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
	 * parameters.
	 */
	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
	if (!asconf_ack)
		goto done;

	/* Process the TLVs contained within the ASCONF chunk. */
	while (chunk_len > 0) {
		err_code = sctp_process_asconf_param(asoc, asconf,
						     asconf_param);
		/* ADDIP 4.1 A7)
		 * If an error response is received for a TLV parameter,
		 * all TLVs with no response before the failed TLV are
		 * considered successful if not reported.  All TLVs after
		 * the failed response are considered unsuccessful unless
		 * a specific success indication is present for the parameter.
		 */
		if (SCTP_ERROR_NO_ERROR != err_code)
			all_param_pass = 0;

		if (!all_param_pass)
			sctp_add_asconf_response(asconf_ack,
						 asconf_param->crr_id, err_code,
						 asconf_param);

		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
		 * an IP address sends an 'Out of Resource' in its response, it
		 * MUST also fail any subsequent add or delete requests bundled
		 * in the ASCONF.
		 */
		if (SCTP_ERROR_RSRC_LOW == err_code)
			goto done;

		/* Move to the next ASCONF param. */
		length = ntohs(asconf_param->param_hdr.length);
		asconf_param = (void *)asconf_param + length;
		chunk_len -= length;
	}

done:
	asoc->peer.addip_serial++;

	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
	 * after freeing the reference to old asconf ack if any.
	 */
	if (asconf_ack) {
		sctp_chunk_hold(asconf_ack);
		list_add_tail(&asconf_ack->transmitted_list,
			      &asoc->asconf_ack_list);
	}

	return asconf_ack;
}

/* Process a asconf parameter that is successfully acked. */
static void sctp_asconf_param_success(struct sctp_association *asoc,
				     sctp_addip_param_t *asconf_param)
{
	struct sctp_af *af;
	union sctp_addr	addr;
	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
	union sctp_addr_param *addr_param;
	struct sctp_transport *transport;
	struct sctp_sockaddr_entry *saddr;

	addr_param = (void *)asconf_param + sizeof(sctp_addip_param_t);

	/* We have checked the packet before, so we do not check again.	*/
	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
	af->from_addr_param(&addr, addr_param, htons(bp->port), 0);

	switch (asconf_param->param_hdr.type) {
	case SCTP_PARAM_ADD_IP:
		/* This is always done in BH context with a socket lock
		 * held, so the list can not change.
		 */
		local_bh_disable();
		list_for_each_entry(saddr, &bp->address_list, list) {
			if (sctp_cmp_addr_exact(&saddr->a, &addr))
				saddr->state = SCTP_ADDR_SRC;
		}
		local_bh_enable();
		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
				transports) {
			dst_release(transport->dst);
			transport->dst = NULL;
		}
		break;
	case SCTP_PARAM_DEL_IP:
		local_bh_disable();
		sctp_del_bind_addr(bp, &addr);
		if (asoc->asconf_addr_del_pending != NULL &&
		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
			kfree(asoc->asconf_addr_del_pending);
			asoc->asconf_addr_del_pending = NULL;
		}
		local_bh_enable();
		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
				transports) {
			dst_release(transport->dst);
			transport->dst = NULL;
		}
		break;
	default:
		break;
	}
}

/* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
 * for the given asconf parameter.  If there is no response for this parameter,
 * return the error code based on the third argument 'no_err'.
 * ADDIP 4.1
 * A7) If an error response is received for a TLV parameter, all TLVs with no
 * response before the failed TLV are considered successful if not reported.
 * All TLVs after the failed response are considered unsuccessful unless a
 * specific success indication is present for the parameter.
 */
static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
				      sctp_addip_param_t *asconf_param,
				      int no_err)
{
	sctp_addip_param_t	*asconf_ack_param;
	sctp_errhdr_t		*err_param;
	int			length;
	int			asconf_ack_len;
	__be16			err_code;

	if (no_err)
		err_code = SCTP_ERROR_NO_ERROR;
	else
		err_code = SCTP_ERROR_REQ_REFUSED;

	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
			     sizeof(sctp_chunkhdr_t);

	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
	 * the first asconf_ack parameter.
	 */
	length = sizeof(sctp_addiphdr_t);
	asconf_ack_param = (sctp_addip_param_t *)(asconf_ack->skb->data +
						  length);
	asconf_ack_len -= length;

	while (asconf_ack_len > 0) {
		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
			switch(asconf_ack_param->param_hdr.type) {
			case SCTP_PARAM_SUCCESS_REPORT:
				return SCTP_ERROR_NO_ERROR;
			case SCTP_PARAM_ERR_CAUSE:
				length = sizeof(sctp_addip_param_t);
				err_param = (void *)asconf_ack_param + length;
				asconf_ack_len -= length;
				if (asconf_ack_len > 0)
					return err_param->cause;
				else
					return SCTP_ERROR_INV_PARAM;
				break;
			default:
				return SCTP_ERROR_INV_PARAM;
			}
		}

		length = ntohs(asconf_ack_param->param_hdr.length);
		asconf_ack_param = (void *)asconf_ack_param + length;
		asconf_ack_len -= length;
	}

	return err_code;
}

/* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
int sctp_process_asconf_ack(struct sctp_association *asoc,
			    struct sctp_chunk *asconf_ack)
{
	struct sctp_chunk	*asconf = asoc->addip_last_asconf;
	union sctp_addr_param	*addr_param;
	sctp_addip_param_t	*asconf_param;
	int	length = 0;
	int	asconf_len = asconf->skb->len;
	int	all_param_pass = 0;
	int	no_err = 1;
	int	retval = 0;
	__be16	err_code = SCTP_ERROR_NO_ERROR;

	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
	 * a pointer to address parameter.
	 */
	length = sizeof(sctp_addip_chunk_t);
	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
	asconf_len -= length;

	/* Skip the address parameter in the last asconf sent and store a
	 * pointer to the first asconf parameter.
	 */
	length = ntohs(addr_param->p.length);
	asconf_param = (void *)addr_param + length;
	asconf_len -= length;

	/* ADDIP 4.1
	 * A8) If there is no response(s) to specific TLV parameter(s), and no
	 * failures are indicated, then all request(s) are considered
	 * successful.
	 */
	if (asconf_ack->skb->len == sizeof(sctp_addiphdr_t))
		all_param_pass = 1;

	/* Process the TLVs contained in the last sent ASCONF chunk. */
	while (asconf_len > 0) {
		if (all_param_pass)
			err_code = SCTP_ERROR_NO_ERROR;
		else {
			err_code = sctp_get_asconf_response(asconf_ack,
							    asconf_param,
							    no_err);
			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
				no_err = 0;
		}

		switch (err_code) {
		case SCTP_ERROR_NO_ERROR:
			sctp_asconf_param_success(asoc, asconf_param);
			break;

		case SCTP_ERROR_RSRC_LOW:
			retval = 1;
			break;

		case SCTP_ERROR_UNKNOWN_PARAM:
			/* Disable sending this type of asconf parameter in
			 * future.
			 */
			asoc->peer.addip_disabled_mask |=
				asconf_param->param_hdr.type;
			break;

		case SCTP_ERROR_REQ_REFUSED:
		case SCTP_ERROR_DEL_LAST_IP:
		case SCTP_ERROR_DEL_SRC_IP:
		default:
			 break;
		}

		/* Skip the processed asconf parameter and move to the next
		 * one.
		 */
		length = ntohs(asconf_param->param_hdr.length);
		asconf_param = (void *)asconf_param + length;
		asconf_len -= length;
	}

	if (no_err && asoc->src_out_of_asoc_ok) {
		asoc->src_out_of_asoc_ok = 0;
		sctp_transport_immediate_rtx(asoc->peer.primary_path);
	}

	/* Free the cached last sent asconf chunk. */
	list_del_init(&asconf->transmitted_list);
	sctp_chunk_free(asconf);
	asoc->addip_last_asconf = NULL;

	return retval;
}

/* Make a FWD TSN chunk. */
struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
				    __u32 new_cum_tsn, size_t nstreams,
				    struct sctp_fwdtsn_skip *skiplist)
{
	struct sctp_chunk *retval = NULL;
	struct sctp_fwdtsn_hdr ftsn_hdr;
	struct sctp_fwdtsn_skip skip;
	size_t hint;
	int i;

	hint = (nstreams + 1) * sizeof(__u32);

	retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);

	if (!retval)
		return NULL;

	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
	retval->subh.fwdtsn_hdr =
		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);

	for (i = 0; i < nstreams; i++) {
		skip.stream = skiplist[i].stream;
		skip.ssn = skiplist[i].ssn;
		sctp_addto_chunk(retval, sizeof(skip), &skip);
	}

	return retval;
}