summaryrefslogtreecommitdiffstats
path: root/packet.c
blob: f997064cb44751c52be1157f916a2e92c37d2902 (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
/* $OpenBSD: packet.c,v 1.252 2017/04/30 23:28:42 djm Exp $ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * This file contains code implementing the packet protocol and communication
 * with the other side.  This same code is used both on client and server side.
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 *
 * SSH2 packet format added by Markus Friedl.
 * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>
#include "openbsd-compat/sys-queue.h"
#include <sys/socket.h>
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif

#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>

#include <errno.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <signal.h>
#include <time.h>

#include <zlib.h>

#include "buffer.h"	/* typedefs XXX */
#include "key.h"	/* typedefs XXX */

#include "xmalloc.h"
#include "crc32.h"
#include "compat.h"
#include "ssh2.h"
#include "cipher.h"
#include "sshkey.h"
#include "kex.h"
#include "digest.h"
#include "mac.h"
#include "log.h"
#include "canohost.h"
#include "misc.h"
#include "channels.h"
#include "ssh.h"
#include "packet.h"
#include "ssherr.h"
#include "sshbuf.h"

#ifdef PACKET_DEBUG
#define DBG(x) x
#else
#define DBG(x)
#endif

#define PACKET_MAX_SIZE (256 * 1024)

struct packet_state {
	u_int32_t seqnr;
	u_int32_t packets;
	u_int64_t blocks;
	u_int64_t bytes;
};

struct packet {
	TAILQ_ENTRY(packet) next;
	u_char type;
	struct sshbuf *payload;
};

struct session_state {
	/*
	 * This variable contains the file descriptors used for
	 * communicating with the other side.  connection_in is used for
	 * reading; connection_out for writing.  These can be the same
	 * descriptor, in which case it is assumed to be a socket.
	 */
	int connection_in;
	int connection_out;

	/* Protocol flags for the remote side. */
	u_int remote_protocol_flags;

	/* Encryption context for receiving data.  Only used for decryption. */
	struct sshcipher_ctx *receive_context;

	/* Encryption context for sending data.  Only used for encryption. */
	struct sshcipher_ctx *send_context;

	/* Buffer for raw input data from the socket. */
	struct sshbuf *input;

	/* Buffer for raw output data going to the socket. */
	struct sshbuf *output;

	/* Buffer for the partial outgoing packet being constructed. */
	struct sshbuf *outgoing_packet;

	/* Buffer for the incoming packet currently being processed. */
	struct sshbuf *incoming_packet;

	/* Scratch buffer for packet compression/decompression. */
	struct sshbuf *compression_buffer;

	/* Incoming/outgoing compression dictionaries */
	z_stream compression_in_stream;
	z_stream compression_out_stream;
	int compression_in_started;
	int compression_out_started;
	int compression_in_failures;
	int compression_out_failures;

	/*
	 * Flag indicating whether packet compression/decompression is
	 * enabled.
	 */
	int packet_compression;

	/* default maximum packet size */
	u_int max_packet_size;

	/* Flag indicating whether this module has been initialized. */
	int initialized;

	/* Set to true if the connection is interactive. */
	int interactive_mode;

	/* Set to true if we are the server side. */
	int server_side;

	/* Set to true if we are authenticated. */
	int after_authentication;

	int keep_alive_timeouts;

	/* The maximum time that we will wait to send or receive a packet */
	int packet_timeout_ms;

	/* Session key information for Encryption and MAC */
	struct newkeys *newkeys[MODE_MAX];
	struct packet_state p_read, p_send;

	/* Volume-based rekeying */
	u_int64_t max_blocks_in, max_blocks_out, rekey_limit;

	/* Time-based rekeying */
	u_int32_t rekey_interval;	/* how often in seconds */
	time_t rekey_time;	/* time of last rekeying */

	/* Session key for protocol v1 */
	u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
	u_int ssh1_keylen;

	/* roundup current message to extra_pad bytes */
	u_char extra_pad;

	/* XXX discard incoming data after MAC error */
	u_int packet_discard;
	size_t packet_discard_mac_already;
	struct sshmac *packet_discard_mac;

	/* Used in packet_read_poll2() */
	u_int packlen;

	/* Used in packet_send2 */
	int rekeying;

	/* Used in ssh_packet_send_mux() */
	int mux;

	/* Used in packet_set_interactive */
	int set_interactive_called;

	/* Used in packet_set_maxsize */
	int set_maxsize_called;

	/* One-off warning about weak ciphers */
	int cipher_warning_done;

	/* Hook for fuzzing inbound packets */
	ssh_packet_hook_fn *hook_in;
	void *hook_in_ctx;

	TAILQ_HEAD(, packet) outgoing;
};

struct ssh *
ssh_alloc_session_state(void)
{
	struct ssh *ssh = NULL;
	struct session_state *state = NULL;

	if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
	    (state = calloc(1, sizeof(*state))) == NULL ||
	    (state->input = sshbuf_new()) == NULL ||
	    (state->output = sshbuf_new()) == NULL ||
	    (state->outgoing_packet = sshbuf_new()) == NULL ||
	    (state->incoming_packet = sshbuf_new()) == NULL)
		goto fail;
	TAILQ_INIT(&state->outgoing);
	TAILQ_INIT(&ssh->private_keys);
	TAILQ_INIT(&ssh->public_keys);
	state->connection_in = -1;
	state->connection_out = -1;
	state->max_packet_size = 32768;
	state->packet_timeout_ms = -1;
	state->p_send.packets = state->p_read.packets = 0;
	state->initialized = 1;
	/*
	 * ssh_packet_send2() needs to queue packets until
	 * we've done the initial key exchange.
	 */
	state->rekeying = 1;
	ssh->state = state;
	return ssh;
 fail:
	if (state) {
		sshbuf_free(state->input);
		sshbuf_free(state->output);
		sshbuf_free(state->incoming_packet);
		sshbuf_free(state->outgoing_packet);
		free(state);
	}
	free(ssh);
	return NULL;
}

void
ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
{
	ssh->state->hook_in = hook;
	ssh->state->hook_in_ctx = ctx;
}

/* Returns nonzero if rekeying is in progress */
int
ssh_packet_is_rekeying(struct ssh *ssh)
{
	return ssh->state->rekeying ||
	    (ssh->kex != NULL && ssh->kex->done == 0);
}

/*
 * Sets the descriptors used for communication.  Disables encryption until
 * packet_set_encryption_key is called.
 */
struct ssh *
ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
{
	struct session_state *state;
	const struct sshcipher *none = cipher_by_name("none");
	int r;

	if (none == NULL) {
		error("%s: cannot load cipher 'none'", __func__);
		return NULL;
	}
	if (ssh == NULL)
		ssh = ssh_alloc_session_state();
	if (ssh == NULL) {
		error("%s: cound not allocate state", __func__);
		return NULL;
	}
	state = ssh->state;
	state->connection_in = fd_in;
	state->connection_out = fd_out;
	if ((r = cipher_init(&state->send_context, none,
	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
	    (r = cipher_init(&state->receive_context, none,
	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
		error("%s: cipher_init failed: %s", __func__, ssh_err(r));
		free(ssh); /* XXX need ssh_free_session_state? */
		return NULL;
	}
	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
	/*
	 * Cache the IP address of the remote connection for use in error
	 * messages that might be generated after the connection has closed.
	 */
	(void)ssh_remote_ipaddr(ssh);
	return ssh;
}

void
ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
{
	struct session_state *state = ssh->state;

	if (timeout <= 0 || count <= 0) {
		state->packet_timeout_ms = -1;
		return;
	}
	if ((INT_MAX / 1000) / count < timeout)
		state->packet_timeout_ms = INT_MAX;
	else
		state->packet_timeout_ms = timeout * count * 1000;
}

void
ssh_packet_set_mux(struct ssh *ssh)
{
	ssh->state->mux = 1;
	ssh->state->rekeying = 0;
}

int
ssh_packet_get_mux(struct ssh *ssh)
{
	return ssh->state->mux;
}

int
ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
{
	va_list args;
	int r;

	free(ssh->log_preamble);
	if (fmt == NULL)
		ssh->log_preamble = NULL;
	else {
		va_start(args, fmt);
		r = vasprintf(&ssh->log_preamble, fmt, args);
		va_end(args);
		if (r < 0 || ssh->log_preamble == NULL)
			return SSH_ERR_ALLOC_FAIL;
	}
	return 0;
}

int
ssh_packet_stop_discard(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	int r;

	if (state->packet_discard_mac) {
		char buf[1024];
		size_t dlen = PACKET_MAX_SIZE;

		if (dlen > state->packet_discard_mac_already)
			dlen -= state->packet_discard_mac_already;
		memset(buf, 'a', sizeof(buf));
		while (sshbuf_len(state->incoming_packet) < dlen)
			if ((r = sshbuf_put(state->incoming_packet, buf,
			    sizeof(buf))) != 0)
				return r;
		(void) mac_compute(state->packet_discard_mac,
		    state->p_read.seqnr,
		    sshbuf_ptr(state->incoming_packet), dlen,
		    NULL, 0);
	}
	logit("Finished discarding for %.200s port %d",
	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
	return SSH_ERR_MAC_INVALID;
}

static int
ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
    struct sshmac *mac, size_t mac_already, u_int discard)
{
	struct session_state *state = ssh->state;
	int r;

	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
			return r;
		return SSH_ERR_MAC_INVALID;
	}
	/*
	 * Record number of bytes over which the mac has already
	 * been computed in order to minimize timing attacks.
	 */
	if (mac && mac->enabled) {
		state->packet_discard_mac = mac;
		state->packet_discard_mac_already = mac_already;
	}
	if (sshbuf_len(state->input) >= discard)
		return ssh_packet_stop_discard(ssh);
	state->packet_discard = discard - sshbuf_len(state->input);
	return 0;
}

/* Returns 1 if remote host is connected via socket, 0 if not. */

int
ssh_packet_connection_is_on_socket(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	struct sockaddr_storage from, to;
	socklen_t fromlen, tolen;

	if (state->connection_in == -1 || state->connection_out == -1)
		return 0;

	/* filedescriptors in and out are the same, so it's a socket */
	if (state->connection_in == state->connection_out)
		return 1;
	fromlen = sizeof(from);
	memset(&from, 0, sizeof(from));
	if (getpeername(state->connection_in, (struct sockaddr *)&from,
	    &fromlen) < 0)
		return 0;
	tolen = sizeof(to);
	memset(&to, 0, sizeof(to));
	if (getpeername(state->connection_out, (struct sockaddr *)&to,
	    &tolen) < 0)
		return 0;
	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
		return 0;
	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
		return 0;
	return 1;
}

void
ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
{
	if (ibytes)
		*ibytes = ssh->state->p_read.bytes;
	if (obytes)
		*obytes = ssh->state->p_send.bytes;
}

int
ssh_packet_connection_af(struct ssh *ssh)
{
	struct sockaddr_storage to;
	socklen_t tolen = sizeof(to);

	memset(&to, 0, sizeof(to));
	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
	    &tolen) < 0)
		return 0;
#ifdef IPV4_IN_IPV6
	if (to.ss_family == AF_INET6 &&
	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
		return AF_INET;
#endif
	return to.ss_family;
}

/* Sets the connection into non-blocking mode. */

void
ssh_packet_set_nonblocking(struct ssh *ssh)
{
	/* Set the socket into non-blocking mode. */
	set_nonblock(ssh->state->connection_in);

	if (ssh->state->connection_out != ssh->state->connection_in)
		set_nonblock(ssh->state->connection_out);
}

/* Returns the socket used for reading. */

int
ssh_packet_get_connection_in(struct ssh *ssh)
{
	return ssh->state->connection_in;
}

/* Returns the descriptor used for writing. */

int
ssh_packet_get_connection_out(struct ssh *ssh)
{
	return ssh->state->connection_out;
}

/*
 * Returns the IP-address of the remote host as a string.  The returned
 * string must not be freed.
 */

const char *
ssh_remote_ipaddr(struct ssh *ssh)
{
	const int sock = ssh->state->connection_in;

	/* Check whether we have cached the ipaddr. */
	if (ssh->remote_ipaddr == NULL) {
		if (ssh_packet_connection_is_on_socket(ssh)) {
			ssh->remote_ipaddr = get_peer_ipaddr(sock);
			ssh->remote_port = get_peer_port(sock);
			ssh->local_ipaddr = get_local_ipaddr(sock);
			ssh->local_port = get_local_port(sock);
		} else {
			ssh->remote_ipaddr = strdup("UNKNOWN");
			ssh->remote_port = 65535;
			ssh->local_ipaddr = strdup("UNKNOWN");
			ssh->local_port = 65535;
		}
	}
	return ssh->remote_ipaddr;
}

/* Returns the port number of the remote host. */

int
ssh_remote_port(struct ssh *ssh)
{
	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
	return ssh->remote_port;
}

/*
 * Returns the IP-address of the local host as a string.  The returned
 * string must not be freed.
 */

const char *
ssh_local_ipaddr(struct ssh *ssh)
{
	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
	return ssh->local_ipaddr;
}

/* Returns the port number of the local host. */

int
ssh_local_port(struct ssh *ssh)
{
	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
	return ssh->local_port;
}

/* Closes the connection and clears and frees internal data structures. */

void
ssh_packet_close(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	u_int mode;

	if (!state->initialized)
		return;
	state->initialized = 0;
	if (state->connection_in == state->connection_out) {
		shutdown(state->connection_out, SHUT_RDWR);
		close(state->connection_out);
	} else {
		close(state->connection_in);
		close(state->connection_out);
	}
	sshbuf_free(state->input);
	sshbuf_free(state->output);
	sshbuf_free(state->outgoing_packet);
	sshbuf_free(state->incoming_packet);
	for (mode = 0; mode < MODE_MAX; mode++)
		kex_free_newkeys(state->newkeys[mode]);
	if (state->compression_buffer) {
		sshbuf_free(state->compression_buffer);
		if (state->compression_out_started) {
			z_streamp stream = &state->compression_out_stream;
			debug("compress outgoing: "
			    "raw data %llu, compressed %llu, factor %.2f",
				(unsigned long long)stream->total_in,
				(unsigned long long)stream->total_out,
				stream->total_in == 0 ? 0.0 :
				(double) stream->total_out / stream->total_in);
			if (state->compression_out_failures == 0)
				deflateEnd(stream);
		}
		if (state->compression_in_started) {
			z_streamp stream = &state->compression_out_stream;
			debug("compress incoming: "
			    "raw data %llu, compressed %llu, factor %.2f",
			    (unsigned long long)stream->total_out,
			    (unsigned long long)stream->total_in,
			    stream->total_out == 0 ? 0.0 :
			    (double) stream->total_in / stream->total_out);
			if (state->compression_in_failures == 0)
				inflateEnd(stream);
		}
	}
	cipher_free(state->send_context);
	cipher_free(state->receive_context);
	state->send_context = state->receive_context = NULL;
	free(ssh->remote_ipaddr);
	ssh->remote_ipaddr = NULL;
	free(ssh->state);
	ssh->state = NULL;
}

/* Sets remote side protocol flags. */

void
ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
{
	ssh->state->remote_protocol_flags = protocol_flags;
}

/* Returns the remote protocol flags set earlier by the above function. */

u_int
ssh_packet_get_protocol_flags(struct ssh *ssh)
{
	return ssh->state->remote_protocol_flags;
}

/*
 * Starts packet compression from the next packet on in both directions.
 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
 */

static int
ssh_packet_init_compression(struct ssh *ssh)
{
	if (!ssh->state->compression_buffer &&
	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
		return SSH_ERR_ALLOC_FAIL;
	return 0;
}

static int
start_compression_out(struct ssh *ssh, int level)
{
	if (level < 1 || level > 9)
		return SSH_ERR_INVALID_ARGUMENT;
	debug("Enabling compression at level %d.", level);
	if (ssh->state->compression_out_started == 1)
		deflateEnd(&ssh->state->compression_out_stream);
	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
	case Z_OK:
		ssh->state->compression_out_started = 1;
		break;
	case Z_MEM_ERROR:
		return SSH_ERR_ALLOC_FAIL;
	default:
		return SSH_ERR_INTERNAL_ERROR;
	}
	return 0;
}

static int
start_compression_in(struct ssh *ssh)
{
	if (ssh->state->compression_in_started == 1)
		inflateEnd(&ssh->state->compression_in_stream);
	switch (inflateInit(&ssh->state->compression_in_stream)) {
	case Z_OK:
		ssh->state->compression_in_started = 1;
		break;
	case Z_MEM_ERROR:
		return SSH_ERR_ALLOC_FAIL;
	default:
		return SSH_ERR_INTERNAL_ERROR;
	}
	return 0;
}

int
ssh_packet_start_compression(struct ssh *ssh, int level)
{
	int r;

	if (ssh->state->packet_compression)
		return SSH_ERR_INTERNAL_ERROR;
	ssh->state->packet_compression = 1;
	if ((r = ssh_packet_init_compression(ssh)) != 0 ||
	    (r = start_compression_in(ssh)) != 0 ||
	    (r = start_compression_out(ssh, level)) != 0)
		return r;
	return 0;
}

/* XXX remove need for separate compression buffer */
static int
compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
{
	u_char buf[4096];
	int r, status;

	if (ssh->state->compression_out_started != 1)
		return SSH_ERR_INTERNAL_ERROR;

	/* This case is not handled below. */
	if (sshbuf_len(in) == 0)
		return 0;

	/* Input is the contents of the input buffer. */
	if ((ssh->state->compression_out_stream.next_in =
	    sshbuf_mutable_ptr(in)) == NULL)
		return SSH_ERR_INTERNAL_ERROR;
	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);

	/* Loop compressing until deflate() returns with avail_out != 0. */
	do {
		/* Set up fixed-size output buffer. */
		ssh->state->compression_out_stream.next_out = buf;
		ssh->state->compression_out_stream.avail_out = sizeof(buf);

		/* Compress as much data into the buffer as possible. */
		status = deflate(&ssh->state->compression_out_stream,
		    Z_PARTIAL_FLUSH);
		switch (status) {
		case Z_MEM_ERROR:
			return SSH_ERR_ALLOC_FAIL;
		case Z_OK:
			/* Append compressed data to output_buffer. */
			if ((r = sshbuf_put(out, buf, sizeof(buf) -
			    ssh->state->compression_out_stream.avail_out)) != 0)
				return r;
			break;
		case Z_STREAM_ERROR:
		default:
			ssh->state->compression_out_failures++;
			return SSH_ERR_INVALID_FORMAT;
		}
	} while (ssh->state->compression_out_stream.avail_out == 0);
	return 0;
}

static int
uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
{
	u_char buf[4096];
	int r, status;

	if (ssh->state->compression_in_started != 1)
		return SSH_ERR_INTERNAL_ERROR;

	if ((ssh->state->compression_in_stream.next_in =
	    sshbuf_mutable_ptr(in)) == NULL)
		return SSH_ERR_INTERNAL_ERROR;
	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);

	for (;;) {
		/* Set up fixed-size output buffer. */
		ssh->state->compression_in_stream.next_out = buf;
		ssh->state->compression_in_stream.avail_out = sizeof(buf);

		status = inflate(&ssh->state->compression_in_stream,
		    Z_PARTIAL_FLUSH);
		switch (status) {
		case Z_OK:
			if ((r = sshbuf_put(out, buf, sizeof(buf) -
			    ssh->state->compression_in_stream.avail_out)) != 0)
				return r;
			break;
		case Z_BUF_ERROR:
			/*
			 * Comments in zlib.h say that we should keep calling
			 * inflate() until we get an error.  This appears to
			 * be the error that we get.
			 */
			return 0;
		case Z_DATA_ERROR:
			return SSH_ERR_INVALID_FORMAT;
		case Z_MEM_ERROR:
			return SSH_ERR_ALLOC_FAIL;
		case Z_STREAM_ERROR:
		default:
			ssh->state->compression_in_failures++;
			return SSH_ERR_INTERNAL_ERROR;
		}
	}
	/* NOTREACHED */
}

/*
 * Causes any further packets to be encrypted using the given key.  The same
 * key is used for both sending and reception.  However, both directions are
 * encrypted independently of each other.
 */

void
ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number)
{
	fatal("no SSH protocol 1 support");
}

int
ssh_set_newkeys(struct ssh *ssh, int mode)
{
	struct session_state *state = ssh->state;
	struct sshenc *enc;
	struct sshmac *mac;
	struct sshcomp *comp;
	struct sshcipher_ctx **ccp;
	struct packet_state *ps;
	u_int64_t *max_blocks;
	const char *wmsg, *dir;
	int r, crypt_type;

	debug2("set_newkeys: mode %d", mode);

	if (mode == MODE_OUT) {
		dir = "output";
		ccp = &state->send_context;
		crypt_type = CIPHER_ENCRYPT;
		ps = &state->p_send;
		max_blocks = &state->max_blocks_out;
	} else {
		dir = "input";
		ccp = &state->receive_context;
		crypt_type = CIPHER_DECRYPT;
		ps = &state->p_read;
		max_blocks = &state->max_blocks_in;
	}
	if (state->newkeys[mode] != NULL) {
		debug("%s: rekeying after %llu %s blocks"
		    " (%llu bytes total)", __func__,
		    (unsigned long long)ps->blocks, dir,
		    (unsigned long long)ps->bytes);
		cipher_free(*ccp);
		*ccp = NULL;
		enc  = &state->newkeys[mode]->enc;
		mac  = &state->newkeys[mode]->mac;
		comp = &state->newkeys[mode]->comp;
		mac_clear(mac);
		explicit_bzero(enc->iv,  enc->iv_len);
		explicit_bzero(enc->key, enc->key_len);
		explicit_bzero(mac->key, mac->key_len);
		free(enc->name);
		free(enc->iv);
		free(enc->key);
		free(mac->name);
		free(mac->key);
		free(comp->name);
		free(state->newkeys[mode]);
	}
	/* note that both bytes and the seqnr are not reset */
	ps->packets = ps->blocks = 0;
	/* move newkeys from kex to state */
	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
		return SSH_ERR_INTERNAL_ERROR;
	ssh->kex->newkeys[mode] = NULL;
	enc  = &state->newkeys[mode]->enc;
	mac  = &state->newkeys[mode]->mac;
	comp = &state->newkeys[mode]->comp;
	if (cipher_authlen(enc->cipher) == 0) {
		if ((r = mac_init(mac)) != 0)
			return r;
	}
	mac->enabled = 1;
	DBG(debug("cipher_init_context: %d", mode));
	if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
	    enc->iv, enc->iv_len, crypt_type)) != 0)
		return r;
	if (!state->cipher_warning_done &&
	    (wmsg = cipher_warning_message(*ccp)) != NULL) {
		error("Warning: %s", wmsg);
		state->cipher_warning_done = 1;
	}
	/* Deleting the keys does not gain extra security */
	/* explicit_bzero(enc->iv,  enc->block_size);
	   explicit_bzero(enc->key, enc->key_len);
	   explicit_bzero(mac->key, mac->key_len); */
	if ((comp->type == COMP_ZLIB ||
	    (comp->type == COMP_DELAYED &&
	     state->after_authentication)) && comp->enabled == 0) {
		if ((r = ssh_packet_init_compression(ssh)) < 0)
			return r;
		if (mode == MODE_OUT) {
			if ((r = start_compression_out(ssh, 6)) != 0)
				return r;
		} else {
			if ((r = start_compression_in(ssh)) != 0)
				return r;
		}
		comp->enabled = 1;
	}
	/*
	 * The 2^(blocksize*2) limit is too expensive for 3DES,
	 * blowfish, etc, so enforce a 1GB limit for small blocksizes.
	 */
	if (enc->block_size >= 16)
		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
	else
		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
	if (state->rekey_limit)
		*max_blocks = MINIMUM(*max_blocks,
		    state->rekey_limit / enc->block_size);
	debug("rekey after %llu blocks", (unsigned long long)*max_blocks);
	return 0;
}

#define MAX_PACKETS	(1U<<31)
static int
ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
{
	struct session_state *state = ssh->state;
	u_int32_t out_blocks;

	/* XXX client can't cope with rekeying pre-auth */
	if (!state->after_authentication)
		return 0;

	/* Haven't keyed yet or KEX in progress. */
	if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh))
		return 0;

	/* Peer can't rekey */
	if (ssh->compat & SSH_BUG_NOREKEY)
		return 0;

	/*
	 * Permit one packet in or out per rekey - this allows us to
	 * make progress when rekey limits are very small.
	 */
	if (state->p_send.packets == 0 && state->p_read.packets == 0)
		return 0;

	/* Time-based rekeying */
	if (state->rekey_interval != 0 &&
	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
		return 1;

	/* Always rekey when MAX_PACKETS sent in either direction */
	if (state->p_send.packets > MAX_PACKETS ||
	    state->p_read.packets > MAX_PACKETS)
		return 1;

	/* Rekey after (cipher-specific) maxiumum blocks */
	out_blocks = ROUNDUP(outbound_packet_len,
	    state->newkeys[MODE_OUT]->enc.block_size);
	return (state->max_blocks_out &&
	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
	    (state->max_blocks_in &&
	    (state->p_read.blocks > state->max_blocks_in));
}

/*
 * Delayed compression for SSH2 is enabled after authentication:
 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
 */
static int
ssh_packet_enable_delayed_compress(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	struct sshcomp *comp = NULL;
	int r, mode;

	/*
	 * Remember that we are past the authentication step, so rekeying
	 * with COMP_DELAYED will turn on compression immediately.
	 */
	state->after_authentication = 1;
	for (mode = 0; mode < MODE_MAX; mode++) {
		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
		if (state->newkeys[mode] == NULL)
			continue;
		comp = &state->newkeys[mode]->comp;
		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
			if ((r = ssh_packet_init_compression(ssh)) != 0)
				return r;
			if (mode == MODE_OUT) {
				if ((r = start_compression_out(ssh, 6)) != 0)
					return r;
			} else {
				if ((r = start_compression_in(ssh)) != 0)
					return r;
			}
			comp->enabled = 1;
		}
	}
	return 0;
}

/* Used to mute debug logging for noisy packet types */
int
ssh_packet_log_type(u_char type)
{
	switch (type) {
	case SSH2_MSG_CHANNEL_DATA:
	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
		return 0;
	default:
		return 1;
	}
}

/*
 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
 */
int
ssh_packet_send2_wrapped(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
	u_char tmp, padlen, pad = 0;
	u_int authlen = 0, aadlen = 0;
	u_int len;
	struct sshenc *enc   = NULL;
	struct sshmac *mac   = NULL;
	struct sshcomp *comp = NULL;
	int r, block_size;

	if (state->newkeys[MODE_OUT] != NULL) {
		enc  = &state->newkeys[MODE_OUT]->enc;
		mac  = &state->newkeys[MODE_OUT]->mac;
		comp = &state->newkeys[MODE_OUT]->comp;
		/* disable mac for authenticated encryption */
		if ((authlen = cipher_authlen(enc->cipher)) != 0)
			mac = NULL;
	}
	block_size = enc ? enc->block_size : 8;
	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;

	type = (sshbuf_ptr(state->outgoing_packet))[5];
	if (ssh_packet_log_type(type))
		debug3("send packet: type %u", type);
#ifdef PACKET_DEBUG
	fprintf(stderr, "plain:     ");
	sshbuf_dump(state->outgoing_packet, stderr);
#endif

	if (comp && comp->enabled) {
		len = sshbuf_len(state->outgoing_packet);
		/* skip header, compress only payload */
		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
			goto out;
		sshbuf_reset(state->compression_buffer);
		if ((r = compress_buffer(ssh, state->outgoing_packet,
		    state->compression_buffer)) != 0)
			goto out;
		sshbuf_reset(state->outgoing_packet);
		if ((r = sshbuf_put(state->outgoing_packet,
		    "\0\0\0\0\0", 5)) != 0 ||
		    (r = sshbuf_putb(state->outgoing_packet,
		    state->compression_buffer)) != 0)
			goto out;
		DBG(debug("compression: raw %d compressed %zd", len,
		    sshbuf_len(state->outgoing_packet)));
	}

	/* sizeof (packet_len + pad_len + payload) */
	len = sshbuf_len(state->outgoing_packet);

	/*
	 * calc size of padding, alloc space, get random data,
	 * minimum padding is 4 bytes
	 */
	len -= aadlen; /* packet length is not encrypted for EtM modes */
	padlen = block_size - (len % block_size);
	if (padlen < 4)
		padlen += block_size;
	if (state->extra_pad) {
		tmp = state->extra_pad;
		state->extra_pad =
		    ROUNDUP(state->extra_pad, block_size);
		/* check if roundup overflowed */
		if (state->extra_pad < tmp)
			return SSH_ERR_INVALID_ARGUMENT;
		tmp = (len + padlen) % state->extra_pad;
		/* Check whether pad calculation below will underflow */
		if (tmp > state->extra_pad)
			return SSH_ERR_INVALID_ARGUMENT;
		pad = state->extra_pad - tmp;
		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
		    __func__, pad, len, padlen, state->extra_pad));
		tmp = padlen;
		padlen += pad;
		/* Check whether padlen calculation overflowed */
		if (padlen < tmp)
			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
		state->extra_pad = 0;
	}
	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
		goto out;
	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
		/* random padding */
		arc4random_buf(cp, padlen);
	} else {
		/* clear padding */
		explicit_bzero(cp, padlen);
	}
	/* sizeof (packet_len + pad_len + payload + padding) */
	len = sshbuf_len(state->outgoing_packet);
	cp = sshbuf_mutable_ptr(state->outgoing_packet);
	if (cp == NULL) {
		r = SSH_ERR_INTERNAL_ERROR;
		goto out;
	}
	/* packet_length includes payload, padding and padding length field */
	POKE_U32(cp, len - 4);
	cp[4] = padlen;
	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
	    len, padlen, aadlen));

	/* compute MAC over seqnr and packet(length fields, payload, padding) */
	if (mac && mac->enabled && !mac->etm) {
		if ((r = mac_compute(mac, state->p_send.seqnr,
		    sshbuf_ptr(state->outgoing_packet), len,
		    macbuf, sizeof(macbuf))) != 0)
			goto out;
		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
	}
	/* encrypt packet and append to output buffer. */
	if ((r = sshbuf_reserve(state->output,
	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
		goto out;
	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
	    sshbuf_ptr(state->outgoing_packet),
	    len - aadlen, aadlen, authlen)) != 0)
		goto out;
	/* append unencrypted MAC */
	if (mac && mac->enabled) {
		if (mac->etm) {
			/* EtM: compute mac over aadlen + cipher text */
			if ((r = mac_compute(mac, state->p_send.seqnr,
			    cp, len, macbuf, sizeof(macbuf))) != 0)
				goto out;
			DBG(debug("done calc MAC(EtM) out #%d",
			    state->p_send.seqnr));
		}
		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
			goto out;
	}
#ifdef PACKET_DEBUG
	fprintf(stderr, "encrypted: ");
	sshbuf_dump(state->output, stderr);
#endif
	/* increment sequence number for outgoing packets */
	if (++state->p_send.seqnr == 0)
		logit("outgoing seqnr wraps around");
	if (++state->p_send.packets == 0)
		if (!(ssh->compat & SSH_BUG_NOREKEY))
			return SSH_ERR_NEED_REKEY;
	state->p_send.blocks += len / block_size;
	state->p_send.bytes += len;
	sshbuf_reset(state->outgoing_packet);

	if (type == SSH2_MSG_NEWKEYS)
		r = ssh_set_newkeys(ssh, MODE_OUT);
	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
		r = ssh_packet_enable_delayed_compress(ssh);
	else
		r = 0;
 out:
	return r;
}

/* returns non-zero if the specified packet type is usec by KEX */
static int
ssh_packet_type_is_kex(u_char type)
{
	return
	    type >= SSH2_MSG_TRANSPORT_MIN &&
	    type <= SSH2_MSG_TRANSPORT_MAX &&
	    type != SSH2_MSG_SERVICE_REQUEST &&
	    type != SSH2_MSG_SERVICE_ACCEPT &&
	    type != SSH2_MSG_EXT_INFO;
}

int
ssh_packet_send2(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	struct packet *p;
	u_char type;
	int r, need_rekey;

	if (sshbuf_len(state->outgoing_packet) < 6)
		return SSH_ERR_INTERNAL_ERROR;
	type = sshbuf_ptr(state->outgoing_packet)[5];
	need_rekey = !ssh_packet_type_is_kex(type) &&
	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));

	/*
	 * During rekeying we can only send key exchange messages.
	 * Queue everything else.
	 */
	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
		if (need_rekey)
			debug3("%s: rekex triggered", __func__);
		debug("enqueue packet: %u", type);
		p = calloc(1, sizeof(*p));
		if (p == NULL)
			return SSH_ERR_ALLOC_FAIL;
		p->type = type;
		p->payload = state->outgoing_packet;
		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
		state->outgoing_packet = sshbuf_new();
		if (state->outgoing_packet == NULL)
			return SSH_ERR_ALLOC_FAIL;
		if (need_rekey) {
			/*
			 * This packet triggered a rekey, so send the
			 * KEXINIT now.
			 * NB. reenters this function via kex_start_rekex().
			 */
			return kex_start_rekex(ssh);
		}
		return 0;
	}

	/* rekeying starts with sending KEXINIT */
	if (type == SSH2_MSG_KEXINIT)
		state->rekeying = 1;

	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
		return r;

	/* after a NEWKEYS message we can send the complete queue */
	if (type == SSH2_MSG_NEWKEYS) {
		state->rekeying = 0;
		state->rekey_time = monotime();
		while ((p = TAILQ_FIRST(&state->outgoing))) {
			type = p->type;
			/*
			 * If this packet triggers a rekex, then skip the
			 * remaining packets in the queue for now.
			 * NB. re-enters this function via kex_start_rekex.
			 */
			if (ssh_packet_need_rekeying(ssh,
			    sshbuf_len(p->payload))) {
				debug3("%s: queued packet triggered rekex",
				    __func__);
				return kex_start_rekex(ssh);
			}
			debug("dequeue packet: %u", type);
			sshbuf_free(state->outgoing_packet);
			state->outgoing_packet = p->payload;
			TAILQ_REMOVE(&state->outgoing, p, next);
			memset(p, 0, sizeof(*p));
			free(p);
			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
				return r;
		}
	}
	return 0;
}

/*
 * Waits until a packet has been received, and returns its type.  Note that
 * no other data is processed until this returns, so this function should not
 * be used during the interactive session.
 */

int
ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
	struct session_state *state = ssh->state;
	int len, r, ms_remain;
	fd_set *setp;
	char buf[8192];
	struct timeval timeout, start, *timeoutp = NULL;

	DBG(debug("packet_read()"));

	setp = calloc(howmany(state->connection_in + 1,
	    NFDBITS), sizeof(fd_mask));
	if (setp == NULL)
		return SSH_ERR_ALLOC_FAIL;

	/*
	 * Since we are blocking, ensure that all written packets have
	 * been sent.
	 */
	if ((r = ssh_packet_write_wait(ssh)) != 0)
		goto out;

	/* Stay in the loop until we have received a complete packet. */
	for (;;) {
		/* Try to read a packet from the buffer. */
		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
		if (r != 0)
			break;
		/* If we got a packet, return it. */
		if (*typep != SSH_MSG_NONE)
			break;
		/*
		 * Otherwise, wait for some data to arrive, add it to the
		 * buffer, and try again.
		 */
		memset(setp, 0, howmany(state->connection_in + 1,
		    NFDBITS) * sizeof(fd_mask));
		FD_SET(state->connection_in, setp);

		if (state->packet_timeout_ms > 0) {
			ms_remain = state->packet_timeout_ms;
			timeoutp = &timeout;
		}
		/* Wait for some data to arrive. */
		for (;;) {
			if (state->packet_timeout_ms != -1) {
				ms_to_timeval(&timeout, ms_remain);
				gettimeofday(&start, NULL);
			}
			if ((r = select(state->connection_in + 1, setp,
			    NULL, NULL, timeoutp)) >= 0)
				break;
			if (errno != EAGAIN && errno != EINTR &&
			    errno != EWOULDBLOCK)
				break;
			if (state->packet_timeout_ms == -1)
				continue;
			ms_subtract_diff(&start, &ms_remain);
			if (ms_remain <= 0) {
				r = 0;
				break;
			}
		}
		if (r == 0) {
			r = SSH_ERR_CONN_TIMEOUT;
			goto out;
		}
		/* Read data from the socket. */
		len = read(state->connection_in, buf, sizeof(buf));
		if (len == 0) {
			r = SSH_ERR_CONN_CLOSED;
			goto out;
		}
		if (len < 0) {
			r = SSH_ERR_SYSTEM_ERROR;
			goto out;
		}

		/* Append it to the buffer. */
		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
			goto out;
	}
 out:
	free(setp);
	return r;
}

int
ssh_packet_read(struct ssh *ssh)
{
	u_char type;
	int r;

	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));
	return type;
}

/*
 * Waits until a packet has been received, verifies that its type matches
 * that given, and gives a fatal error and exits if there is a mismatch.
 */

int
ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
{
	int r;
	u_char type;

	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
		return r;
	if (type != expected_type) {
		if ((r = sshpkt_disconnect(ssh,
		    "Protocol error: expected packet type %d, got %d",
		    expected_type, type)) != 0)
			return r;
		return SSH_ERR_PROTOCOL_ERROR;
	}
	return 0;
}

static int
ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
	struct session_state *state = ssh->state;
	const u_char *cp;
	size_t need;
	int r;

	if (ssh->kex)
		return SSH_ERR_INTERNAL_ERROR;
	*typep = SSH_MSG_NONE;
	cp = sshbuf_ptr(state->input);
	if (state->packlen == 0) {
		if (sshbuf_len(state->input) < 4 + 1)
			return 0; /* packet is incomplete */
		state->packlen = PEEK_U32(cp);
		if (state->packlen < 4 + 1 ||
		    state->packlen > PACKET_MAX_SIZE)
			return SSH_ERR_MESSAGE_INCOMPLETE;
	}
	need = state->packlen + 4;
	if (sshbuf_len(state->input) < need)
		return 0; /* packet is incomplete */
	sshbuf_reset(state->incoming_packet);
	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
	    state->packlen)) != 0 ||
	    (r = sshbuf_consume(state->input, need)) != 0 ||
	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
		return r;
	if (ssh_packet_log_type(*typep))
		debug3("%s: type %u", __func__, *typep);
	/* sshbuf_dump(state->incoming_packet, stderr); */
	/* reset for next packet */
	state->packlen = 0;
	return r;
}

int
ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
	struct session_state *state = ssh->state;
	u_int padlen, need;
	u_char *cp;
	u_int maclen, aadlen = 0, authlen = 0, block_size;
	struct sshenc *enc   = NULL;
	struct sshmac *mac   = NULL;
	struct sshcomp *comp = NULL;
	int r;

	if (state->mux)
		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);

	*typep = SSH_MSG_NONE;

	if (state->packet_discard)
		return 0;

	if (state->newkeys[MODE_IN] != NULL) {
		enc  = &state->newkeys[MODE_IN]->enc;
		mac  = &state->newkeys[MODE_IN]->mac;
		comp = &state->newkeys[MODE_IN]->comp;
		/* disable mac for authenticated encryption */
		if ((authlen = cipher_authlen(enc->cipher)) != 0)
			mac = NULL;
	}
	maclen = mac && mac->enabled ? mac->mac_len : 0;
	block_size = enc ? enc->block_size : 8;
	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;

	if (aadlen && state->packlen == 0) {
		if (cipher_get_length(state->receive_context,
		    &state->packlen, state->p_read.seqnr,
		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
			return 0;
		if (state->packlen < 1 + 4 ||
		    state->packlen > PACKET_MAX_SIZE) {
#ifdef PACKET_DEBUG
			sshbuf_dump(state->input, stderr);
#endif
			logit("Bad packet length %u.", state->packlen);
			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
				return r;
			return SSH_ERR_CONN_CORRUPT;
		}
		sshbuf_reset(state->incoming_packet);
	} else if (state->packlen == 0) {
		/*
		 * check if input size is less than the cipher block size,
		 * decrypt first block and extract length of incoming packet
		 */
		if (sshbuf_len(state->input) < block_size)
			return 0;
		sshbuf_reset(state->incoming_packet);
		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
		    &cp)) != 0)
			goto out;
		if ((r = cipher_crypt(state->receive_context,
		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
		    block_size, 0, 0)) != 0)
			goto out;
		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
		if (state->packlen < 1 + 4 ||
		    state->packlen > PACKET_MAX_SIZE) {
#ifdef PACKET_DEBUG
			fprintf(stderr, "input: \n");
			sshbuf_dump(state->input, stderr);
			fprintf(stderr, "incoming_packet: \n");
			sshbuf_dump(state->incoming_packet, stderr);
#endif
			logit("Bad packet length %u.", state->packlen);
			return ssh_packet_start_discard(ssh, enc, mac, 0,
			    PACKET_MAX_SIZE);
		}
		if ((r = sshbuf_consume(state->input, block_size)) != 0)
			goto out;
	}
	DBG(debug("input: packet len %u", state->packlen+4));

	if (aadlen) {
		/* only the payload is encrypted */
		need = state->packlen;
	} else {
		/*
		 * the payload size and the payload are encrypted, but we
		 * have a partial packet of block_size bytes
		 */
		need = 4 + state->packlen - block_size;
	}
	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
	if (need % block_size != 0) {
		logit("padding error: need %d block %d mod %d",
		    need, block_size, need % block_size);
		return ssh_packet_start_discard(ssh, enc, mac, 0,
		    PACKET_MAX_SIZE - block_size);
	}
	/*
	 * check if the entire packet has been received and
	 * decrypt into incoming_packet:
	 * 'aadlen' bytes are unencrypted, but authenticated.
	 * 'need' bytes are encrypted, followed by either
	 * 'authlen' bytes of authentication tag or
	 * 'maclen' bytes of message authentication code.
	 */
	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
		return 0; /* packet is incomplete */
#ifdef PACKET_DEBUG
	fprintf(stderr, "read_poll enc/full: ");
	sshbuf_dump(state->input, stderr);
#endif
	/* EtM: check mac over encrypted input */
	if (mac && mac->enabled && mac->etm) {
		if ((r = mac_check(mac, state->p_read.seqnr,
		    sshbuf_ptr(state->input), aadlen + need,
		    sshbuf_ptr(state->input) + aadlen + need + authlen,
		    maclen)) != 0) {
			if (r == SSH_ERR_MAC_INVALID)
				logit("Corrupted MAC on input.");
			goto out;
		}
	}
	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
	    &cp)) != 0)
		goto out;
	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
		goto out;
	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
		goto out;
	if (mac && mac->enabled) {
		/* Not EtM: check MAC over cleartext */
		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
		    sshbuf_ptr(state->incoming_packet),
		    sshbuf_len(state->incoming_packet),
		    sshbuf_ptr(state->input), maclen)) != 0) {
			if (r != SSH_ERR_MAC_INVALID)
				goto out;
			logit("Corrupted MAC on input.");
			if (need + block_size > PACKET_MAX_SIZE)
				return SSH_ERR_INTERNAL_ERROR;
			return ssh_packet_start_discard(ssh, enc, mac,
			    sshbuf_len(state->incoming_packet),
			    PACKET_MAX_SIZE - need - block_size);
		}
		/* Remove MAC from input buffer */
		DBG(debug("MAC #%d ok", state->p_read.seqnr));
		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
			goto out;
	}
	if (seqnr_p != NULL)
		*seqnr_p = state->p_read.seqnr;
	if (++state->p_read.seqnr == 0)
		logit("incoming seqnr wraps around");
	if (++state->p_read.packets == 0)
		if (!(ssh->compat & SSH_BUG_NOREKEY))
			return SSH_ERR_NEED_REKEY;
	state->p_read.blocks += (state->packlen + 4) / block_size;
	state->p_read.bytes += state->packlen + 4;

	/* get padlen */
	padlen = sshbuf_ptr(state->incoming_packet)[4];
	DBG(debug("input: padlen %d", padlen));
	if (padlen < 4)	{
		if ((r = sshpkt_disconnect(ssh,
		    "Corrupted padlen %d on input.", padlen)) != 0 ||
		    (r = ssh_packet_write_wait(ssh)) != 0)
			return r;
		return SSH_ERR_CONN_CORRUPT;
	}

	/* skip packet size + padlen, discard padding */
	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
		goto out;

	DBG(debug("input: len before de-compress %zd",
	    sshbuf_len(state->incoming_packet)));
	if (comp && comp->enabled) {
		sshbuf_reset(state->compression_buffer);
		if ((r = uncompress_buffer(ssh, state->incoming_packet,
		    state->compression_buffer)) != 0)
			goto out;
		sshbuf_reset(state->incoming_packet);
		if ((r = sshbuf_putb(state->incoming_packet,
		    state->compression_buffer)) != 0)
			goto out;
		DBG(debug("input: len after de-compress %zd",
		    sshbuf_len(state->incoming_packet)));
	}
	/*
	 * get packet type, implies consume.
	 * return length of payload (without type field)
	 */
	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
		goto out;
	if (ssh_packet_log_type(*typep))
		debug3("receive packet: type %u", *typep);
	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
		if ((r = sshpkt_disconnect(ssh,
		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
		    (r = ssh_packet_write_wait(ssh)) != 0)
			return r;
		return SSH_ERR_PROTOCOL_ERROR;
	}
	if (state->hook_in != NULL &&
	    (r = state->hook_in(ssh, state->incoming_packet, typep,
	    state->hook_in_ctx)) != 0)
		return r;
	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
		r = ssh_packet_enable_delayed_compress(ssh);
	else
		r = 0;
#ifdef PACKET_DEBUG
	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
	sshbuf_dump(state->incoming_packet, stderr);
#endif
	/* reset for next packet */
	state->packlen = 0;

	/* do we need to rekey? */
	if (ssh_packet_need_rekeying(ssh, 0)) {
		debug3("%s: rekex triggered", __func__);
		if ((r = kex_start_rekex(ssh)) != 0)
			return r;
	}
 out:
	return r;
}

int
ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
	struct session_state *state = ssh->state;
	u_int reason, seqnr;
	int r;
	u_char *msg;

	for (;;) {
		msg = NULL;
		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
		if (r != 0)
			return r;
		if (*typep) {
			state->keep_alive_timeouts = 0;
			DBG(debug("received packet type %d", *typep));
		}
		switch (*typep) {
		case SSH2_MSG_IGNORE:
			debug3("Received SSH2_MSG_IGNORE");
			break;
		case SSH2_MSG_DEBUG:
			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
				free(msg);
				return r;
			}
			debug("Remote: %.900s", msg);
			free(msg);
			break;
		case SSH2_MSG_DISCONNECT:
			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
				return r;
			/* Ignore normal client exit notifications */
			do_log2(ssh->state->server_side &&
			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
			    "Received disconnect from %s port %d:"
			    "%u: %.400s", ssh_remote_ipaddr(ssh),
			    ssh_remote_port(ssh), reason, msg);
			free(msg);
			return SSH_ERR_DISCONNECTED;
		case SSH2_MSG_UNIMPLEMENTED:
			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
				return r;
			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
			    seqnr);
			break;
		default:
			return 0;
		}
	}
}

/*
 * Buffers the given amount of input characters.  This is intended to be used
 * together with packet_read_poll.
 */

int
ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
{
	struct session_state *state = ssh->state;
	int r;

	if (state->packet_discard) {
		state->keep_alive_timeouts = 0; /* ?? */
		if (len >= state->packet_discard) {
			if ((r = ssh_packet_stop_discard(ssh)) != 0)
				return r;
		}
		state->packet_discard -= len;
		return 0;
	}
	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
		return r;

	return 0;
}

int
ssh_packet_remaining(struct ssh *ssh)
{
	return sshbuf_len(ssh->state->incoming_packet);
}

/*
 * Sends a diagnostic message from the server to the client.  This message
 * can be sent at any time (but not while constructing another message). The
 * message is printed immediately, but only if the client is being executed
 * in verbose mode.  These messages are primarily intended to ease debugging
 * authentication problems.   The length of the formatted message must not
 * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
 */
void
ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
{
	char buf[1024];
	va_list args;
	int r;

	if ((ssh->compat & SSH_BUG_DEBUG))
		return;

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);

	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
	    (r = sshpkt_send(ssh)) != 0 ||
	    (r = ssh_packet_write_wait(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));
}

static void
fmt_connection_id(struct ssh *ssh, char *s, size_t l)
{
	snprintf(s, l, "%.200s%s%s port %d",
	    ssh->log_preamble ? ssh->log_preamble : "",
	    ssh->log_preamble ? " " : "",
	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
}

/*
 * Pretty-print connection-terminating errors and exit.
 */
void
sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
{
	char remote_id[512];

	fmt_connection_id(ssh, remote_id, sizeof(remote_id));

	switch (r) {
	case SSH_ERR_CONN_CLOSED:
		logdie("Connection closed by %s", remote_id);
	case SSH_ERR_CONN_TIMEOUT:
		logdie("Connection %s %s timed out",
		    ssh->state->server_side ? "from" : "to", remote_id);
	case SSH_ERR_DISCONNECTED:
		logdie("Disconnected from %s", remote_id);
	case SSH_ERR_SYSTEM_ERROR:
		if (errno == ECONNRESET)
			logdie("Connection reset by %s", remote_id);
		/* FALLTHROUGH */
	case SSH_ERR_NO_CIPHER_ALG_MATCH:
	case SSH_ERR_NO_MAC_ALG_MATCH:
	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
	case SSH_ERR_NO_KEX_ALG_MATCH:
	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
		if (ssh && ssh->kex && ssh->kex->failed_choice) {
			logdie("Unable to negotiate with %s: %s. "
			    "Their offer: %s", remote_id, ssh_err(r),
			    ssh->kex->failed_choice);
		}
		/* FALLTHROUGH */
	default:
		logdie("%s%sConnection %s %s: %s",
		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
		    ssh->state->server_side ? "from" : "to",
		    remote_id, ssh_err(r));
	}
}

/*
 * Logs the error plus constructs and sends a disconnect packet, closes the
 * connection, and exits.  This function never returns. The error message
 * should not contain a newline.  The length of the formatted message must
 * not exceed 1024 bytes.
 */
void
ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
{
	char buf[1024], remote_id[512];
	va_list args;
	static int disconnecting = 0;
	int r;

	if (disconnecting)	/* Guard against recursive invocations. */
		fatal("packet_disconnect called recursively.");
	disconnecting = 1;

	/*
	 * Format the message.  Note that the caller must make sure the
	 * message is of limited size.
	 */
	fmt_connection_id(ssh, remote_id, sizeof(remote_id));
	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);

	/* Display the error locally */
	logit("Disconnecting %s: %.100s", remote_id, buf);

	/*
	 * Send the disconnect message to the other side, and wait
	 * for it to get sent.
	 */
	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
		sshpkt_fatal(ssh, __func__, r);

	if ((r = ssh_packet_write_wait(ssh)) != 0)
		sshpkt_fatal(ssh, __func__, r);

	/* Close the connection. */
	ssh_packet_close(ssh);
	cleanup_exit(255);
}

/*
 * Checks if there is any buffered output, and tries to write some of
 * the output.
 */
int
ssh_packet_write_poll(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	int len = sshbuf_len(state->output);
	int r;

	if (len > 0) {
		len = write(state->connection_out,
		    sshbuf_ptr(state->output), len);
		if (len == -1) {
			if (errno == EINTR || errno == EAGAIN ||
			    errno == EWOULDBLOCK)
				return 0;
			return SSH_ERR_SYSTEM_ERROR;
		}
		if (len == 0)
			return SSH_ERR_CONN_CLOSED;
		if ((r = sshbuf_consume(state->output, len)) != 0)
			return r;
	}
	return 0;
}

/*
 * Calls packet_write_poll repeatedly until all pending output data has been
 * written.
 */
int
ssh_packet_write_wait(struct ssh *ssh)
{
	fd_set *setp;
	int ret, r, ms_remain = 0;
	struct timeval start, timeout, *timeoutp = NULL;
	struct session_state *state = ssh->state;

	setp = calloc(howmany(state->connection_out + 1,
	    NFDBITS), sizeof(fd_mask));
	if (setp == NULL)
		return SSH_ERR_ALLOC_FAIL;
	if ((r = ssh_packet_write_poll(ssh)) != 0) {
		free(setp);
		return r;
	}
	while (ssh_packet_have_data_to_write(ssh)) {
		memset(setp, 0, howmany(state->connection_out + 1,
		    NFDBITS) * sizeof(fd_mask));
		FD_SET(state->connection_out, setp);

		if (state->packet_timeout_ms > 0) {
			ms_remain = state->packet_timeout_ms;
			timeoutp = &timeout;
		}
		for (;;) {
			if (state->packet_timeout_ms != -1) {
				ms_to_timeval(&timeout, ms_remain);
				gettimeofday(&start, NULL);
			}
			if ((ret = select(state->connection_out + 1,
			    NULL, setp, NULL, timeoutp)) >= 0)
				break;
			if (errno != EAGAIN && errno != EINTR &&
			    errno != EWOULDBLOCK)
				break;
			if (state->packet_timeout_ms == -1)
				continue;
			ms_subtract_diff(&start, &ms_remain);
			if (ms_remain <= 0) {
				ret = 0;
				break;
			}
		}
		if (ret == 0) {
			free(setp);
			return SSH_ERR_CONN_TIMEOUT;
		}
		if ((r = ssh_packet_write_poll(ssh)) != 0) {
			free(setp);
			return r;
		}
	}
	free(setp);
	return 0;
}

/* Returns true if there is buffered data to write to the connection. */

int
ssh_packet_have_data_to_write(struct ssh *ssh)
{
	return sshbuf_len(ssh->state->output) != 0;
}

/* Returns true if there is not too much data to write to the connection. */

int
ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
{
	if (ssh->state->interactive_mode)
		return sshbuf_len(ssh->state->output) < 16384;
	else
		return sshbuf_len(ssh->state->output) < 128 * 1024;
}

void
ssh_packet_set_tos(struct ssh *ssh, int tos)
{
#ifndef IP_TOS_IS_BROKEN
	if (!ssh_packet_connection_is_on_socket(ssh))
		return;
	switch (ssh_packet_connection_af(ssh)) {
# ifdef IP_TOS
	case AF_INET:
		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
		if (setsockopt(ssh->state->connection_in,
		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
			error("setsockopt IP_TOS %d: %.100s:",
			    tos, strerror(errno));
		break;
# endif /* IP_TOS */
# ifdef IPV6_TCLASS
	case AF_INET6:
		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
		if (setsockopt(ssh->state->connection_in,
		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
			error("setsockopt IPV6_TCLASS %d: %.100s:",
			    tos, strerror(errno));
		break;
# endif /* IPV6_TCLASS */
	}
#endif /* IP_TOS_IS_BROKEN */
}

/* Informs that the current session is interactive.  Sets IP flags for that. */

void
ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
{
	struct session_state *state = ssh->state;

	if (state->set_interactive_called)
		return;
	state->set_interactive_called = 1;

	/* Record that we are in interactive mode. */
	state->interactive_mode = interactive;

	/* Only set socket options if using a socket.  */
	if (!ssh_packet_connection_is_on_socket(ssh))
		return;
	set_nodelay(state->connection_in);
	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
	    qos_bulk);
}

/* Returns true if the current connection is interactive. */

int
ssh_packet_is_interactive(struct ssh *ssh)
{
	return ssh->state->interactive_mode;
}

int
ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
{
	struct session_state *state = ssh->state;

	if (state->set_maxsize_called) {
		logit("packet_set_maxsize: called twice: old %d new %d",
		    state->max_packet_size, s);
		return -1;
	}
	if (s < 4 * 1024 || s > 1024 * 1024) {
		logit("packet_set_maxsize: bad size %d", s);
		return -1;
	}
	state->set_maxsize_called = 1;
	debug("packet_set_maxsize: setting to %d", s);
	state->max_packet_size = s;
	return s;
}

int
ssh_packet_inc_alive_timeouts(struct ssh *ssh)
{
	return ++ssh->state->keep_alive_timeouts;
}

void
ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
{
	ssh->state->keep_alive_timeouts = ka;
}

u_int
ssh_packet_get_maxsize(struct ssh *ssh)
{
	return ssh->state->max_packet_size;
}

/*
 * 9.2.  Ignored Data Message
 *
 *   byte      SSH_MSG_IGNORE
 *   string    data
 *
 * All implementations MUST understand (and ignore) this message at any
 * time (after receiving the protocol version). No implementation is
 * required to send them. This message can be used as an additional
 * protection measure against advanced traffic analysis techniques.
 */
void
ssh_packet_send_ignore(struct ssh *ssh, int nbytes)
{
	u_int32_t rnd = 0;
	int r, i;

	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));
	for (i = 0; i < nbytes; i++) {
		if (i % 4 == 0)
			rnd = arc4random();
		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
			fatal("%s: %s", __func__, ssh_err(r));
		rnd >>= 8;
	}
}

void
ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
{
	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
	    (unsigned int)seconds);
	ssh->state->rekey_limit = bytes;
	ssh->state->rekey_interval = seconds;
}

time_t
ssh_packet_get_rekey_timeout(struct ssh *ssh)
{
	time_t seconds;

	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
	    monotime();
	return (seconds <= 0 ? 1 : seconds);
}

void
ssh_packet_set_server(struct ssh *ssh)
{
	ssh->state->server_side = 1;
}

void
ssh_packet_set_authenticated(struct ssh *ssh)
{
	ssh->state->after_authentication = 1;
}

void *
ssh_packet_get_input(struct ssh *ssh)
{
	return (void *)ssh->state->input;
}

void *
ssh_packet_get_output(struct ssh *ssh)
{
	return (void *)ssh->state->output;
}

/* Reset after_authentication and reset compression in post-auth privsep */
static int
ssh_packet_set_postauth(struct ssh *ssh)
{
	int r;

	debug("%s: called", __func__);
	/* This was set in net child, but is not visible in user child */
	ssh->state->after_authentication = 1;
	ssh->state->rekeying = 0;
	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
		return r;
	return 0;
}

/* Packet state (de-)serialization for privsep */

/* turn kex into a blob for packet state serialization */
static int
kex_to_blob(struct sshbuf *m, struct kex *kex)
{
	int r;

	if ((r = sshbuf_put_string(m, kex->session_id,
	    kex->session_id_len)) != 0 ||
	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
	    (r = sshbuf_put_u32(m, kex->flags)) != 0 ||
	    (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 ||
	    (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0)
		return r;
	return 0;
}

/* turn key exchange results into a blob for packet state serialization */
static int
newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
{
	struct sshbuf *b;
	struct sshcipher_ctx *cc;
	struct sshcomp *comp;
	struct sshenc *enc;
	struct sshmac *mac;
	struct newkeys *newkey;
	int r;

	if ((newkey = ssh->state->newkeys[mode]) == NULL)
		return SSH_ERR_INTERNAL_ERROR;
	enc = &newkey->enc;
	mac = &newkey->mac;
	comp = &newkey->comp;
	cc = (mode == MODE_OUT) ? ssh->state->send_context :
	    ssh->state->receive_context;
	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
		return r;
	if ((b = sshbuf_new()) == NULL)
		return SSH_ERR_ALLOC_FAIL;
	/* The cipher struct is constant and shared, you export pointer */
	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
	    (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
		goto out;
	if (cipher_authlen(enc->cipher) == 0) {
		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
			goto out;
	}
	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
		goto out;
	r = sshbuf_put_stringb(m, b);
 out:
	sshbuf_free(b);
	return r;
}

/* serialize packet state into a blob */
int
ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
{
	struct session_state *state = ssh->state;
	u_char *p;
	size_t slen, rlen;
	int r;

	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0)
		return r;

	slen = cipher_get_keycontext(state->send_context, NULL);
	rlen = cipher_get_keycontext(state->receive_context, NULL);
	if ((r = sshbuf_put_u32(m, slen)) != 0 ||
	    (r = sshbuf_reserve(m, slen, &p)) != 0)
		return r;
	if (cipher_get_keycontext(state->send_context, p) != (int)slen)
		return SSH_ERR_INTERNAL_ERROR;
	if ((r = sshbuf_put_u32(m, rlen)) != 0 ||
	    (r = sshbuf_reserve(m, rlen, &p)) != 0)
		return r;
	if (cipher_get_keycontext(state->receive_context, p) != (int)rlen)
		return SSH_ERR_INTERNAL_ERROR;
	if ((r = sshbuf_put_stringb(m, state->input)) != 0 ||
	    (r = sshbuf_put_stringb(m, state->output)) != 0)
		return r;

	return 0;
}

/* restore key exchange results from blob for packet state de-serialization */
static int
newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
{
	struct sshbuf *b = NULL;
	struct sshcomp *comp;
	struct sshenc *enc;
	struct sshmac *mac;
	struct newkeys *newkey = NULL;
	size_t keylen, ivlen, maclen;
	int r;

	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = sshbuf_froms(m, &b)) != 0)
		goto out;
#ifdef DEBUG_PK
	sshbuf_dump(b, stderr);
#endif
	enc = &newkey->enc;
	mac = &newkey->mac;
	comp = &newkey->comp;

	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
	    (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
		goto out;
	if (cipher_authlen(enc->cipher) == 0) {
		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
			goto out;
		if ((r = mac_setup(mac, mac->name)) != 0)
			goto out;
		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
			goto out;
		if (maclen > mac->key_len) {
			r = SSH_ERR_INVALID_FORMAT;
			goto out;
		}
		mac->key_len = maclen;
	}
	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
		goto out;
	if (enc->name == NULL ||
	    cipher_by_name(enc->name) != enc->cipher) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	if (sshbuf_len(b) != 0) {
		r = SSH_ERR_INVALID_FORMAT;
		goto out;
	}
	enc->key_len = keylen;
	enc->iv_len = ivlen;
	ssh->kex->newkeys[mode] = newkey;
	newkey = NULL;
	r = 0;
 out:
	free(newkey);
	sshbuf_free(b);
	return r;
}

/* restore kex from blob for packet state de-serialization */
static int
kex_from_blob(struct sshbuf *m, struct kex **kexp)
{
	struct kex *kex;
	int r;

	if ((kex = calloc(1, sizeof(struct kex))) == NULL ||
	    (kex->my = sshbuf_new()) == NULL ||
	    (kex->peer = sshbuf_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
	    (r = sshbuf_get_u32(m, &kex->flags)) != 0 ||
	    (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 ||
	    (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0)
		goto out;
	kex->server = 1;
	kex->done = 1;
	r = 0;
 out:
	if (r != 0 || kexp == NULL) {
		if (kex != NULL) {
			sshbuf_free(kex->my);
			sshbuf_free(kex->peer);
			free(kex);
		}
		if (kexp != NULL)
			*kexp = NULL;
	} else {
		*kexp = kex;
	}
	return r;
}

/*
 * Restore packet state from content of blob 'm' (de-serialization).
 * Note that 'm' will be partially consumed on parsing or any other errors.
 */
int
ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
{
	struct session_state *state = ssh->state;
	const u_char *keyin, *keyout, *input, *output;
	size_t rlen, slen, ilen, olen;
	int r;

	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
		return r;
	/*
	 * We set the time here so that in post-auth privsep slave we
	 * count from the completion of the authentication.
	 */
	state->rekey_time = monotime();
	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
		return r;

	if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 ||
	    (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0)
		return r;
	if (cipher_get_keycontext(state->send_context, NULL) != (int)slen ||
	    cipher_get_keycontext(state->receive_context, NULL) != (int)rlen)
		return SSH_ERR_INVALID_FORMAT;
	cipher_set_keycontext(state->send_context, keyout);
	cipher_set_keycontext(state->receive_context, keyin);

	if ((r = ssh_packet_set_postauth(ssh)) != 0)
		return r;

	sshbuf_reset(state->input);
	sshbuf_reset(state->output);
	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
	    (r = sshbuf_put(state->output, output, olen)) != 0)
		return r;

	if (sshbuf_len(m))
		return SSH_ERR_INVALID_FORMAT;
	debug3("%s: done", __func__);
	return 0;
}

/* NEW API */

/* put data to the outgoing packet */

int
sshpkt_put(struct ssh *ssh, const void *v, size_t len)
{
	return sshbuf_put(ssh->state->outgoing_packet, v, len);
}

int
sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
{
	return sshbuf_putb(ssh->state->outgoing_packet, b);
}

int
sshpkt_put_u8(struct ssh *ssh, u_char val)
{
	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
}

int
sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
{
	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
}

int
sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
{
	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
}

int
sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
{
	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
}

int
sshpkt_put_cstring(struct ssh *ssh, const void *v)
{
	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
}

int
sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
{
	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
}

#ifdef WITH_OPENSSL
#ifdef OPENSSL_HAS_ECC
int
sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
{
	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
}
#endif /* OPENSSL_HAS_ECC */


int
sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
{
	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
}
#endif /* WITH_OPENSSL */

/* fetch data from the incoming packet */

int
sshpkt_get(struct ssh *ssh, void *valp, size_t len)
{
	return sshbuf_get(ssh->state->incoming_packet, valp, len);
}

int
sshpkt_get_u8(struct ssh *ssh, u_char *valp)
{
	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
}

int
sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
{
	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
}

int
sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
{
	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
}

int
sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
{
	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
}

int
sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
{
	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
}

int
sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
{
	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
}

#ifdef WITH_OPENSSL
#ifdef OPENSSL_HAS_ECC
int
sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
{
	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
}
#endif /* OPENSSL_HAS_ECC */


int
sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v)
{
	return sshbuf_get_bignum2(ssh->state->incoming_packet, v);
}
#endif /* WITH_OPENSSL */

int
sshpkt_get_end(struct ssh *ssh)
{
	if (sshbuf_len(ssh->state->incoming_packet) > 0)
		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
	return 0;
}

const u_char *
sshpkt_ptr(struct ssh *ssh, size_t *lenp)
{
	if (lenp != NULL)
		*lenp = sshbuf_len(ssh->state->incoming_packet);
	return sshbuf_ptr(ssh->state->incoming_packet);
}

/* start a new packet */

int
sshpkt_start(struct ssh *ssh, u_char type)
{
	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */

	DBG(debug("packet_start[%d]", type));
	memset(buf, 0, sizeof(buf));
	buf[sizeof(buf) - 1] = type;
	sshbuf_reset(ssh->state->outgoing_packet);
	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
}

static int
ssh_packet_send_mux(struct ssh *ssh)
{
	struct session_state *state = ssh->state;
	u_char type, *cp;
	size_t len;
	int r;

	if (ssh->kex)
		return SSH_ERR_INTERNAL_ERROR;
	len = sshbuf_len(state->outgoing_packet);
	if (len < 6)
		return SSH_ERR_INTERNAL_ERROR;
	cp = sshbuf_mutable_ptr(state->outgoing_packet);
	type = cp[5];
	if (ssh_packet_log_type(type))
		debug3("%s: type %u", __func__, type);
	/* drop everything, but the connection protocol */
	if (type >= SSH2_MSG_CONNECTION_MIN &&
	    type <= SSH2_MSG_CONNECTION_MAX) {
		POKE_U32(cp, len - 4);
		if ((r = sshbuf_putb(state->output,
		    state->outgoing_packet)) != 0)
			return r;
		/* sshbuf_dump(state->output, stderr); */
	}
	sshbuf_reset(state->outgoing_packet);
	return 0;
}

/* send it */

int
sshpkt_send(struct ssh *ssh)
{
	if (ssh->state && ssh->state->mux)
		return ssh_packet_send_mux(ssh);
	return ssh_packet_send2(ssh);
}

int
sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
{
	char buf[1024];
	va_list args;
	int r;

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);

	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		return r;
	return 0;
}

/* roundup current message to pad bytes */
int
sshpkt_add_padding(struct ssh *ssh, u_char pad)
{
	ssh->state->extra_pad = pad;
	return 0;
}