summaryrefslogtreecommitdiffstats
path: root/libxtables/xtables.c
blob: e3e444acbbaa26c019ee93eff9c47e6c48dd367d (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
/*
 * (C) 2000-2006 by the netfilter coreteam <coreteam@netfilter.org>:
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This program 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 this program; if not, write to the Free Software
 *	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include "config.h"
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <netdb.h>
#include <spawn.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netinet/ether.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/types.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#if defined(HAVE_LINUX_MAGIC_H)
#	include <linux/magic.h> /* for PROC_SUPER_MAGIC */
#elif defined(HAVE_LINUX_PROC_FS_H)
#	include <linux/proc_fs.h>	/* Linux 2.4 */
#else
#	define PROC_SUPER_MAGIC	0x9fa0
#endif

#include <xtables.h>
#include <limits.h> /* INT_MAX in ip_tables.h/ip6_tables.h */
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <libiptc/libxtc.h>
#include <libiptc/linux_list.h>

#ifndef NO_SHARED_LIBS
#include <dlfcn.h>
#endif
#ifndef IPT_SO_GET_REVISION_MATCH /* Old kernel source. */
#	define IPT_SO_GET_REVISION_MATCH	(IPT_BASE_CTL + 2)
#	define IPT_SO_GET_REVISION_TARGET	(IPT_BASE_CTL + 3)
#endif
#ifndef IP6T_SO_GET_REVISION_MATCH /* Old kernel source. */
#	define IP6T_SO_GET_REVISION_MATCH	68
#	define IP6T_SO_GET_REVISION_TARGET	69
#endif
#include <getopt.h>
#include "iptables/internal.h"

#define NPROTO	255

#ifndef PROC_SYS_MODPROBE
#define PROC_SYS_MODPROBE "/proc/sys/kernel/modprobe"
#endif

#ifndef ETH_ALEN
#define ETH_ALEN 6
#endif

/* we need this for ip6?tables-restore.  ip6?tables-restore.c sets line to the
 * current line of the input file, in order  to give a more precise error
 * message.  ip6?tables itself doesn't need this, so it is initialized to the
 * magic number of -1 */
int line = -1;

void basic_exit_err(enum xtables_exittype status, const char *msg, ...) __attribute__((noreturn, format(printf,2,3)));

struct xtables_globals *xt_params = NULL;

void basic_exit_err(enum xtables_exittype status, const char *msg, ...)
{
	va_list args;

	va_start(args, msg);
	fprintf(stderr, "%s v%s: ", xt_params->program_name, xt_params->program_version);
	vfprintf(stderr, msg, args);
	va_end(args);
	fprintf(stderr, "\n");
	if (status == PARAMETER_PROBLEM) {
		if (line != -1)
			fprintf(stderr, "Error occurred at line: %d\n", line);
		fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
				xt_params->program_name, xt_params->program_name);
	} else if (status == VERSION_PROBLEM) {
		fprintf(stderr,
			"Perhaps %s or your kernel needs to be upgraded.\n",
			xt_params->program_name);
	}
	/* On error paths, make sure that we don't leak memory */
	xtables_free_opts(1);
	exit(status);
}

void xtables_free_opts(int unused)
{
	if (xt_params->opts != xt_params->orig_opts) {
		free(xt_params->opts);
		xt_params->opts = NULL;
	}
}

struct option *xtables_merge_options(struct option *orig_opts,
				     struct option *oldopts,
				     const struct option *newopts,
				     unsigned int *option_offset)
{
	unsigned int num_oold = 0, num_old = 0, num_new = 0, i;
	struct option *merge, *mp;

	if (newopts == NULL)
		return oldopts;

	for (num_oold = 0; orig_opts[num_oold].name; num_oold++) ;
	if (oldopts != NULL)
		for (num_old = 0; oldopts[num_old].name; num_old++) ;
	for (num_new = 0; newopts[num_new].name; num_new++) ;

	/*
	 * Since @oldopts also has @orig_opts already (and does so at the
	 * start), skip these entries.
	 */
	if (oldopts != NULL) {
		oldopts += num_oold;
		num_old -= num_oold;
	}

	merge = malloc(sizeof(*mp) * (num_oold + num_old + num_new + 1));
	if (merge == NULL)
		return NULL;

	/* Let the base options -[ADI...] have precedence over everything */
	memcpy(merge, orig_opts, sizeof(*mp) * num_oold);
	mp = merge + num_oold;

	/* Second, the new options */
	xt_params->option_offset += XT_OPTION_OFFSET_SCALE;
	*option_offset = xt_params->option_offset;
	memcpy(mp, newopts, sizeof(*mp) * num_new);

	for (i = 0; i < num_new; ++i, ++mp)
		mp->val += *option_offset;

	/* Third, the old options */
	if (oldopts != NULL) {
		memcpy(mp, oldopts, sizeof(*mp) * num_old);
		mp += num_old;
	}
	xtables_free_opts(0);

	/* Clear trailing entry */
	memset(mp, 0, sizeof(*mp));
	return merge;
}

static const struct xtables_afinfo afinfo_ipv4 = {
	.kmod          = "ip_tables",
	.proc_exists   = "/proc/net/ip_tables_names",
	.libprefix     = "libipt_",
	.family	       = NFPROTO_IPV4,
	.ipproto       = IPPROTO_IP,
	.so_rev_match  = IPT_SO_GET_REVISION_MATCH,
	.so_rev_target = IPT_SO_GET_REVISION_TARGET,
};

static const struct xtables_afinfo afinfo_ipv6 = {
	.kmod          = "ip6_tables",
	.proc_exists   = "/proc/net/ip6_tables_names",
	.libprefix     = "libip6t_",
	.family        = NFPROTO_IPV6,
	.ipproto       = IPPROTO_IPV6,
	.so_rev_match  = IP6T_SO_GET_REVISION_MATCH,
	.so_rev_target = IP6T_SO_GET_REVISION_TARGET,
};

/* Dummy families for arptables-compat and ebtables-compat. Leave structure
 * fields that we don't use unset.
 */
static const struct xtables_afinfo afinfo_bridge = {
	.libprefix     = "libebt_",
	.family        = NFPROTO_BRIDGE,
};

static const struct xtables_afinfo afinfo_arp = {
	.libprefix     = "libarpt_",
	.family        = NFPROTO_ARP,
};

const struct xtables_afinfo *afinfo;

/* Search path for Xtables .so files */
static const char *xtables_libdir;

/* the path to command to load kernel module */
const char *xtables_modprobe_program;

/* Keep track of matches/targets pending full registration: linked lists. */
struct xtables_match *xtables_pending_matches;
struct xtables_target *xtables_pending_targets;

/* Keep track of fully registered external matches/targets: linked lists. */
struct xtables_match *xtables_matches;
struct xtables_target *xtables_targets;

/* Fully register a match/target which was previously partially registered. */
static bool xtables_fully_register_pending_match(struct xtables_match *me,
						 struct xtables_match *prev);
static bool xtables_fully_register_pending_target(struct xtables_target *me,
						  struct xtables_target *prev);

#ifndef NO_SHARED_LIBS
/* registry for loaded shared objects to close later */
struct dlreg {
	struct dlreg *next;
	void *handle;
};
static struct dlreg *dlreg = NULL;

static int dlreg_add(void *handle)
{
	struct dlreg *new = malloc(sizeof(*new));

	if (!new)
		return -1;

	new->handle = handle;
	new->next = dlreg;
	dlreg = new;
	return 0;
}

static void dlreg_free(void)
{
	struct dlreg *next;

	while (dlreg) {
		next = dlreg->next;
		dlclose(dlreg->handle);
		free(dlreg);
		dlreg = next;
	}
}
#endif

struct notarget {
	struct hlist_node node;
	char name[];
};

#define NOTARGET_HSIZE	512
static struct hlist_head notargets[NOTARGET_HSIZE];

static void notargets_hlist_init(void)
{
	int i;

	for (i = 0; i < NOTARGET_HSIZE; i++)
		INIT_HLIST_HEAD(&notargets[i]);
}

static void notargets_hlist_free(void)
{
	struct hlist_node *pos, *n;
	struct notarget *cur;
	int i;

	for (i = 0; i < NOTARGET_HSIZE; i++) {
		hlist_for_each_entry_safe(cur, pos, n, &notargets[i], node) {
			hlist_del(&cur->node);
			free(cur);
		}
	}
}

static uint32_t djb_hash(const char *key)
{
	uint32_t i, hash = 5381;

	for (i = 0; i < strlen(key); i++)
		hash = ((hash << 5) + hash) + key[i];

	return hash;
}

static struct notarget *notargets_hlist_lookup(const char *name)
{
	uint32_t key = djb_hash(name) % NOTARGET_HSIZE;
	struct hlist_node *node;
	struct notarget *cur;

	hlist_for_each_entry(cur, node, &notargets[key], node) {
		if (!strcmp(name, cur->name))
			return cur;
	}
	return NULL;
}

static void notargets_hlist_insert(const char *name)
{
	struct notarget *cur;

	if (!name)
		return;

	cur = xtables_malloc(sizeof(*cur) + strlen(name) + 1);
	strcpy(cur->name, name);
	hlist_add_head(&cur->node, &notargets[djb_hash(name) % NOTARGET_HSIZE]);
}

void xtables_announce_chain(const char *name)
{
	if (!notargets_hlist_lookup(name))
		notargets_hlist_insert(name);
}

void xtables_init(void)
{
	/* xtables cannot be used with setuid in a safe way. */
	if (getuid() != geteuid())
		_exit(111);

	xtables_libdir = getenv("XTABLES_LIBDIR");
	if (xtables_libdir != NULL)
		return;
	xtables_libdir = getenv("IPTABLES_LIB_DIR");
	if (xtables_libdir != NULL) {
		fprintf(stderr, "IPTABLES_LIB_DIR is deprecated, "
		        "use XTABLES_LIBDIR.\n");
		return;
	}
	/*
	 * Well yes, IP6TABLES_LIB_DIR is of lower priority over
	 * IPTABLES_LIB_DIR since this moved to libxtables; I think that is ok
	 * for these env vars are deprecated anyhow, and in light of the
	 * (shared) libxt_*.so files, makes less sense to have
	 * IPTABLES_LIB_DIR != IP6TABLES_LIB_DIR.
	 */
	xtables_libdir = getenv("IP6TABLES_LIB_DIR");
	if (xtables_libdir != NULL) {
		fprintf(stderr, "IP6TABLES_LIB_DIR is deprecated, "
		        "use XTABLES_LIBDIR.\n");
		return;
	}
	xtables_libdir = XTABLES_LIBDIR;

	notargets_hlist_init();
}

void xtables_fini(void)
{
#ifndef NO_SHARED_LIBS
	dlreg_free();
#endif
	notargets_hlist_free();
}

void xtables_set_nfproto(uint8_t nfproto)
{
	switch (nfproto) {
	case NFPROTO_IPV4:
		afinfo = &afinfo_ipv4;
		break;
	case NFPROTO_IPV6:
		afinfo = &afinfo_ipv6;
		break;
	case NFPROTO_BRIDGE:
		afinfo = &afinfo_bridge;
		break;
	case NFPROTO_ARP:
		afinfo = &afinfo_arp;
		break;
	default:
		fprintf(stderr, "libxtables: unhandled NFPROTO in %s\n",
		        __func__);
	}
}

/**
 * xtables_set_params - set the global parameters used by xtables
 * @xtp:	input xtables_globals structure
 *
 * The app is expected to pass a valid xtables_globals data-filled
 * with proper values
 * @xtp cannot be NULL
 *
 * Returns -1 on failure to set and 0 on success
 */
int xtables_set_params(struct xtables_globals *xtp)
{
	if (!xtp) {
		fprintf(stderr, "%s: Illegal global params\n",__func__);
		return -1;
	}

	xt_params = xtp;

	if (!xt_params->exit_err)
		xt_params->exit_err = basic_exit_err;

	return 0;
}

int xtables_init_all(struct xtables_globals *xtp, uint8_t nfproto)
{
	xtables_init();
	xtables_set_nfproto(nfproto);
	return xtables_set_params(xtp);
}

/**
 * xtables_*alloc - wrappers that exit on failure
 */
void *xtables_calloc(size_t count, size_t size)
{
	void *p;

	if ((p = calloc(count, size)) == NULL) {
		perror("ip[6]tables: calloc failed");
		exit(1);
	}

	return p;
}

void *xtables_malloc(size_t size)
{
	void *p;

	if ((p = malloc(size)) == NULL) {
		perror("ip[6]tables: malloc failed");
		exit(1);
	}

	return p;
}

void *xtables_realloc(void *ptr, size_t size)
{
	void *p;

	if ((p = realloc(ptr, size)) == NULL) {
		perror("ip[6]tables: realloc failed");
		exit(1);
	}

	return p;
}

char *xtables_strdup(const char *s)
{
	char *dup = strdup(s);

	if (!dup) {
		perror("ip[6]tables: strdup failed");
		exit(1);
	}

	return dup;
}

static char *get_modprobe(void)
{
	int procfile;
	char *ret;
	int count;

	procfile = open(PROC_SYS_MODPROBE, O_RDONLY);
	if (procfile < 0)
		return NULL;
	if (fcntl(procfile, F_SETFD, FD_CLOEXEC) == -1) {
		fprintf(stderr, "Could not set close on exec: %s\n",
			strerror(errno));
		exit(1);
	}

	ret = malloc(PATH_MAX);
	if (ret) {
		count = read(procfile, ret, PATH_MAX);
		if (count > 0 && count < PATH_MAX)
		{
			if (ret[count - 1] == '\n')
				ret[count - 1] = '\0';
			else
				ret[count] = '\0';
			close(procfile);
			return ret;
		}
	}
	free(ret);
	close(procfile);
	return NULL;
}

int xtables_insmod(const char *modname, const char *modprobe, bool quiet)
{
	char *buf = NULL;
	char *argv[4];
	int status;
	pid_t pid;

	/* If they don't explicitly set it, read out of kernel */
	if (!modprobe) {
		buf = get_modprobe();
		if (!buf)
			return -1;
		modprobe = buf;
	}

	argv[0] = (char *)modprobe;
	argv[1] = (char *)modname;
	argv[2] = quiet ? "-q" : NULL;
	argv[3] = NULL;

	/*
	 * Need to flush the buffer, or the child may output it again
	 * when switching the program thru execv.
	 */
	fflush(stdout);

	if (posix_spawn(&pid, argv[0], NULL, NULL, argv, NULL)) {
		free(buf);
		return -1;
	} else {
		waitpid(pid, &status, 0);
	}

	free(buf);
	if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
		return 0;
	return -1;
}

/* return true if a given file exists within procfs */
static bool proc_file_exists(const char *filename)
{
	struct stat s;
	struct statfs f;

	if (lstat(filename, &s))
		return false;
	if (!S_ISREG(s.st_mode))
		return false;
	if (statfs(filename, &f))
		return false;
	if (f.f_type != PROC_SUPER_MAGIC)
		return false;
	return true;
}

int xtables_load_ko(const char *modprobe, bool quiet)
{
	static bool loaded = false;
	int ret;

	if (loaded)
		return 0;

	if (proc_file_exists(afinfo->proc_exists)) {
		loaded = true;
		return 0;
	};

	ret = xtables_insmod(afinfo->kmod, modprobe, quiet);
	if (ret == 0)
		loaded = true;

	return ret;
}

/**
 * xtables_strtou{i,l} - string to number conversion
 * @s:	input string
 * @end:	like strtoul's "end" pointer
 * @value:	pointer for result
 * @min:	minimum accepted value
 * @max:	maximum accepted value
 *
 * If @end is NULL, we assume the caller wants a "strict strtoul", and hence
 * "15a" is rejected.
 * In either case, the value obtained is compared for min-max compliance.
 * Base is always 0, i.e. autodetect depending on @s.
 *
 * Returns true/false whether number was accepted. On failure, *value has
 * undefined contents.
 */
bool xtables_strtoul(const char *s, char **end, uintmax_t *value,
                     uintmax_t min, uintmax_t max)
{
	uintmax_t v;
	const char *p;
	char *my_end;

	errno = 0;
	/* Since strtoul allows leading minus, we have to check for ourself. */
	for (p = s; isspace(*p); ++p)
		;
	if (*p == '-')
		return false;
	v = strtoumax(s, &my_end, 0);
	if (my_end == s)
		return false;
	if (end != NULL)
		*end = my_end;

	if (errno != ERANGE && min <= v && (max == 0 || v <= max)) {
		if (value != NULL)
			*value = v;
		if (end == NULL)
			return *my_end == '\0';
		return true;
	}

	return false;
}

bool xtables_strtoui(const char *s, char **end, unsigned int *value,
                     unsigned int min, unsigned int max)
{
	uintmax_t v;
	bool ret;

	ret = xtables_strtoul(s, end, &v, min, max);
	if (ret && value != NULL)
		*value = v;
	return ret;
}

int xtables_service_to_port(const char *name, const char *proto)
{
	struct servent *service;

	if ((service = getservbyname(name, proto)) != NULL)
		return ntohs((unsigned short) service->s_port);

	return -1;
}

uint16_t xtables_parse_port(const char *port, const char *proto)
{
	unsigned int portnum;

	if (xtables_strtoui(port, NULL, &portnum, 0, UINT16_MAX) ||
	    (portnum = xtables_service_to_port(port, proto)) != (unsigned)-1)
		return portnum;

	xt_params->exit_err(PARAMETER_PROBLEM,
		   "invalid port/service `%s' specified", port);
}

void xtables_parse_interface(const char *arg, char *vianame,
			     unsigned char *mask)
{
	unsigned int vialen = strlen(arg);
	unsigned int i;

	memset(mask, 0, IFNAMSIZ);
	memset(vianame, 0, IFNAMSIZ);

	if (vialen + 1 > IFNAMSIZ)
		xt_params->exit_err(PARAMETER_PROBLEM,
			   "interface name `%s' must be shorter than IFNAMSIZ"
			   " (%i)", arg, IFNAMSIZ-1);

	strcpy(vianame, arg);
	if (vialen == 0)
		return;
	else if (vianame[vialen - 1] == '+') {
		memset(mask, 0xFF, vialen - 1);
		/* Don't remove `+' here! -HW */
	} else {
		/* Include nul-terminator in match */
		memset(mask, 0xFF, vialen + 1);
	}

	/* Display warning on invalid characters */
	for (i = 0; vianame[i]; i++) {
		if (vianame[i] == '/' || vianame[i] == ' ') {
			fprintf(stderr,	"Warning: weird character in interface"
				" `%s' ('/' and ' ' are not allowed by the kernel).\n",
				vianame);
			break;
		}
	}
}

#ifndef NO_SHARED_LIBS
static void *load_extension(const char *search_path, const char *af_prefix,
    const char *name, bool is_target)
{
	const char *all_prefixes[] = {af_prefix, "libxt_", NULL};
	const char **prefix;
	const char *dir = search_path, *next;
	void *ptr = NULL;
	struct stat sb;
	char path[256];

	do {
		next = strchr(dir, ':');
		if (next == NULL)
			next = dir + strlen(dir);

		for (prefix = all_prefixes; *prefix != NULL; ++prefix) {
			void *handle;

			snprintf(path, sizeof(path), "%.*s/%s%s.so",
			         (unsigned int)(next - dir), dir,
			         *prefix, name);

			if (stat(path, &sb) != 0) {
				if (errno == ENOENT)
					continue;
				fprintf(stderr, "%s: %s\n", path,
					strerror(errno));
				return NULL;
			}
			handle = dlopen(path, RTLD_NOW);
			if (handle == NULL) {
				fprintf(stderr, "%s: %s\n", path, dlerror());
				break;
			}

			dlreg_add(handle);

			if (is_target)
				ptr = xtables_find_target(name, XTF_DONT_LOAD);
			else
				ptr = xtables_find_match(name,
				      XTF_DONT_LOAD, NULL);

			if (ptr != NULL)
				return ptr;

			errno = ENOENT;
			return NULL;
		}
		dir = next + 1;
	} while (*next != '\0');

	return NULL;
}
#endif

static bool extension_cmp(const char *name1, const char *name2, uint32_t family)
{
	if (strcmp(name1, name2) == 0 &&
	    (family == afinfo->family ||
	     family == NFPROTO_UNSPEC))
		return true;

	return false;
}

struct xtables_match *
xtables_find_match(const char *name, enum xtables_tryload tryload,
		   struct xtables_rule_match **matches)
{
	struct xtables_match *prev = NULL;
	struct xtables_match **dptr;
	struct xtables_match *ptr;
	const char *icmp6 = "icmp6";
	bool found = false;
	bool seen = false;

	if (strlen(name) >= XT_EXTENSION_MAXNAMELEN)
		xtables_error(PARAMETER_PROBLEM,
			   "Invalid match name \"%s\" (%u chars max)",
			   name, XT_EXTENSION_MAXNAMELEN - 1);

	/* This is ugly as hell. Nonetheless, there is no way of changing
	 * this without hurting backwards compatibility */
	if ( (strcmp(name,"icmpv6") == 0) ||
	     (strcmp(name,"ipv6-icmp") == 0) ||
	     (strcmp(name,"icmp6") == 0) )
		name = icmp6;

	/* Trigger delayed initialization */
	for (dptr = &xtables_pending_matches; *dptr; ) {
		if (extension_cmp(name, (*dptr)->name, (*dptr)->family)) {
			ptr = *dptr;
			*dptr = (*dptr)->next;
			seen = true;
			if (!found &&
			    xtables_fully_register_pending_match(ptr, prev)) {
				found = true;
				prev = ptr;
				continue;
			} else if (prev) {
				continue;
			}
			*dptr = ptr;
		}
		dptr = &((*dptr)->next);
	}

	if (seen && !found)
		fprintf(stderr,
			"Warning: Extension %s is not supported, missing kernel module?\n",
			name);

	for (ptr = xtables_matches; ptr; ptr = ptr->next) {
		if (extension_cmp(name, ptr->name, ptr->family)) {
			struct xtables_match *clone;

			/* First match of this type: */
			if (ptr->m == NULL)
				break;

			/* Second and subsequent clones */
			clone = xtables_malloc(sizeof(struct xtables_match));
			memcpy(clone, ptr, sizeof(struct xtables_match));
			clone->udata = NULL;
			clone->mflags = 0;
			/* This is a clone: */
			clone->next = clone;

			ptr = clone;
			break;
		}
	}

#ifndef NO_SHARED_LIBS
	if (!ptr && tryload != XTF_DONT_LOAD && tryload != XTF_DURING_LOAD) {
		ptr = load_extension(xtables_libdir, afinfo->libprefix,
		      name, false);

		if (ptr == NULL && tryload == XTF_LOAD_MUST_SUCCEED)
			xt_params->exit_err(PARAMETER_PROBLEM,
				   "Couldn't load match `%s':%s\n",
				   name, strerror(errno));
	}
#else
	if (ptr && !ptr->loaded) {
		if (tryload != XTF_DONT_LOAD)
			ptr->loaded = 1;
		else
			ptr = NULL;
	}
	if(!ptr && (tryload == XTF_LOAD_MUST_SUCCEED)) {
		xt_params->exit_err(PARAMETER_PROBLEM,
			   "Couldn't find match `%s'\n", name);
	}
#endif

	if (ptr && matches) {
		struct xtables_rule_match **i;
		struct xtables_rule_match *newentry;

		newentry = xtables_malloc(sizeof(struct xtables_rule_match));

		for (i = matches; *i; i = &(*i)->next) {
			if (extension_cmp(name, (*i)->match->name,
					  (*i)->match->family))
				(*i)->completed = true;
		}
		newentry->match = ptr;
		newentry->completed = false;
		newentry->next = NULL;
		*i = newentry;
	}

	return ptr;
}

struct xtables_match *
xtables_find_match_revision(const char *name, enum xtables_tryload tryload,
			    struct xtables_match *match, int revision)
{
	if (!match) {
		match = xtables_find_match(name, tryload, NULL);
		if (!match)
			return NULL;
	}

	while (1) {
		if (match->revision == revision)
			return match;
		match = match->next;
		if (!match)
			return NULL;
		if (!extension_cmp(name, match->name, match->family))
			return NULL;
	}
}

struct xtables_target *
xtables_find_target(const char *name, enum xtables_tryload tryload)
{
	struct xtables_target *prev = NULL;
	struct xtables_target **dptr;
	struct xtables_target *ptr;
	bool found = false;
	bool seen = false;

	/* Standard target? */
	if (strcmp(name, "") == 0
	    || strcmp(name, XTC_LABEL_ACCEPT) == 0
	    || strcmp(name, XTC_LABEL_DROP) == 0
	    || strcmp(name, XTC_LABEL_QUEUE) == 0
	    || strcmp(name, XTC_LABEL_RETURN) == 0)
		name = "standard";
	/* known non-target? */
	else if (notargets_hlist_lookup(name) &&
		 tryload != XTF_LOAD_MUST_SUCCEED)
		return NULL;

	/* Trigger delayed initialization */
	for (dptr = &xtables_pending_targets; *dptr; ) {
		if (extension_cmp(name, (*dptr)->name, (*dptr)->family)) {
			ptr = *dptr;
			*dptr = (*dptr)->next;
			seen = true;
			if (!found &&
			    xtables_fully_register_pending_target(ptr, prev)) {
				found = true;
				prev = ptr;
				continue;
			} else if (prev) {
				continue;
			}
			*dptr = ptr;
		}
		dptr = &((*dptr)->next);
	}

	if (seen && !found)
		fprintf(stderr,
			"Warning: Extension %s is not supported, missing kernel module?\n",
			name);

	for (ptr = xtables_targets; ptr; ptr = ptr->next) {
		if (extension_cmp(name, ptr->name, ptr->family)) {
			struct xtables_target *clone;

			/* First target of this type: */
			if (ptr->t == NULL)
				break;

			/* Second and subsequent clones */
			clone = xtables_malloc(sizeof(struct xtables_target));
			memcpy(clone, ptr, sizeof(struct xtables_target));
			clone->udata = NULL;
			clone->tflags = 0;
			/* This is a clone: */
			clone->next = clone;

			ptr = clone;
			break;
		}
	}

#ifndef NO_SHARED_LIBS
	if (!ptr && tryload != XTF_DONT_LOAD && tryload != XTF_DURING_LOAD) {
		ptr = load_extension(xtables_libdir, afinfo->libprefix,
		      name, true);

		if (ptr == NULL && tryload == XTF_LOAD_MUST_SUCCEED)
			xt_params->exit_err(PARAMETER_PROBLEM,
				   "Couldn't load target `%s':%s\n",
				   name, strerror(errno));
	}
#else
	if (ptr && !ptr->loaded) {
		if (tryload != XTF_DONT_LOAD)
			ptr->loaded = 1;
		else
			ptr = NULL;
	}
	if (ptr == NULL && tryload == XTF_LOAD_MUST_SUCCEED) {
		xt_params->exit_err(PARAMETER_PROBLEM,
			   "Couldn't find target `%s'\n", name);
	}
#endif

	if (ptr)
		ptr->used = 1;
	else
		notargets_hlist_insert(name);

	return ptr;
}

struct xtables_target *
xtables_find_target_revision(const char *name, enum xtables_tryload tryload,
			     struct xtables_target *target, int revision)
{
	if (!target) {
		target = xtables_find_target(name, tryload);
		if (!target)
			return NULL;
	}

	while (1) {
		if (target->revision == revision)
			return target;
		target = target->next;
		if (!target)
			return NULL;
		if (!extension_cmp(name, target->name, target->family))
			return NULL;
	}
}

int xtables_compatible_revision(const char *name, uint8_t revision, int opt)
{
	struct xt_get_revision rev;
	socklen_t s = sizeof(rev);
	int max_rev, sockfd;

	sockfd = socket(afinfo->family, SOCK_RAW, IPPROTO_RAW);
	if (sockfd < 0) {
		if (errno == EPERM) {
			/* revision 0 is always supported. */
			if (revision != 0)
				fprintf(stderr, "%s: Could not determine whether "
						"revision %u is supported, "
						"assuming it is.\n",
					name, revision);
			return 1;
		}
		fprintf(stderr, "Could not open socket to kernel: %s\n",
			strerror(errno));
		exit(1);
	}

	if (fcntl(sockfd, F_SETFD, FD_CLOEXEC) == -1) {
		fprintf(stderr, "Could not set close on exec: %s\n",
			strerror(errno));
		exit(1);
	}

	xtables_load_ko(xtables_modprobe_program, true);

	strncpy(rev.name, name, XT_EXTENSION_MAXNAMELEN - 1);
	rev.name[XT_EXTENSION_MAXNAMELEN - 1] = '\0';
	rev.revision = revision;

	max_rev = getsockopt(sockfd, afinfo->ipproto, opt, &rev, &s);
	if (max_rev < 0) {
		/* Definitely don't support this? */
		if (errno == ENOENT || errno == EPROTONOSUPPORT) {
			close(sockfd);
			/* Pretend revision 0 support for better error messaging */
			if (revision == 0)
				fprintf(stderr,
					"Warning: Extension %s revision 0 not supported, missing kernel module?\n",
					name);
			return (revision == 0);
		} else if (errno == ENOPROTOOPT) {
			close(sockfd);
			/* Assume only revision 0 support (old kernel) */
			return (revision == 0);
		} else {
			fprintf(stderr, "getsockopt failed strangely: %s\n",
				strerror(errno));
			exit(1);
		}
	}
	close(sockfd);
	return 1;
}


static int compatible_match_revision(const char *name, uint8_t revision)
{
	return xt_params->compat_rev(name, revision, afinfo->so_rev_match);
}

static int compatible_target_revision(const char *name, uint8_t revision)
{
	return xt_params->compat_rev(name, revision, afinfo->so_rev_target);
}

static void xtables_check_options(const char *name, const struct option *opt)
{
	for (; opt->name != NULL; ++opt)
		if (opt->val < 0 || opt->val >= XT_OPTION_OFFSET_SCALE) {
			fprintf(stderr, "%s: Extension %s uses invalid "
			        "option value %d\n",xt_params->program_name,
			        name, opt->val);
			exit(1);
		}
}

static int xtables_match_prefer(const struct xtables_match *a,
				const struct xtables_match *b);

void xtables_register_match(struct xtables_match *me)
{
	struct xtables_match **pos;
	bool seen_myself = false;

	if (me->next) {
		fprintf(stderr, "%s: match \"%s\" already registered\n",
			xt_params->program_name, me->name);
		exit(1);
	}

	if (me->version == NULL) {
		fprintf(stderr, "%s: match %s<%u> is missing a version\n",
		        xt_params->program_name, me->name, me->revision);
		exit(1);
	}

	if (me->size != XT_ALIGN(me->size)) {
		fprintf(stderr, "%s: match \"%s\" has invalid size %u.\n",
		        xt_params->program_name, me->name,
		        (unsigned int)me->size);
		exit(1);
	}

	if (strcmp(me->version, XTABLES_VERSION) != 0) {
		fprintf(stderr, "%s: match \"%s\" has version \"%s\", "
		        "but \"%s\" is required.\n",
			xt_params->program_name, me->name,
			me->version, XTABLES_VERSION);
		exit(1);
	}

	if (strlen(me->name) >= XT_EXTENSION_MAXNAMELEN) {
		fprintf(stderr, "%s: match `%s' has invalid name\n",
			xt_params->program_name, me->name);
		exit(1);
	}

	if (me->real_name && strlen(me->real_name) >= XT_EXTENSION_MAXNAMELEN) {
		fprintf(stderr, "%s: match `%s' has invalid real name\n",
			xt_params->program_name, me->real_name);
		exit(1);
	}

	if (me->family >= NPROTO) {
		fprintf(stderr,
			"%s: BUG: match %s has invalid protocol family\n",
			xt_params->program_name, me->name);
		exit(1);
	}

	if (me->x6_options != NULL)
		xtables_option_metavalidate(me->name, me->x6_options);
	if (me->extra_opts != NULL)
		xtables_check_options(me->name, me->extra_opts);

	/* order into linked list of matches pending full registration */
	for (pos = &xtables_pending_matches; *pos; pos = &(*pos)->next) {
		/* group by name and family */
		if (strcmp(me->name, (*pos)->name) ||
		    me->family != (*pos)->family) {
			if (seen_myself)
				break; /* end of own group, append to it */
			continue;
		}
		/* found own group */
		seen_myself = true;
		if (xtables_match_prefer(me, *pos) >= 0)
			break; /* put preferred items first in group */
	}
	/* if own group was not found, prepend item */
	if (!*pos && !seen_myself)
		pos = &xtables_pending_matches;

	me->next = *pos;
	*pos = me;
#ifdef DEBUG
	printf("%s: inserted match %s (family %d, revision %d):\n",
			__func__, me->name, me->family, me->revision);
	for (pos = &xtables_pending_matches; *pos; pos = &(*pos)->next) {
		printf("%s:\tmatch %s (family %d, revision %d)\n", __func__,
		       (*pos)->name, (*pos)->family, (*pos)->revision);
	}
#endif
}

/**
 * Compare two actions for their preference
 * @a:	one action
 * @b: 	another
 *
 * Like strcmp, returns a negative number if @a is less preferred than @b,
 * positive number if @a is more preferred than @b, or zero if equally
 * preferred.
 */
static int
xtables_mt_prefer(bool a_alias, unsigned int a_rev, unsigned int a_fam,
		  bool b_alias, unsigned int b_rev, unsigned int b_fam)
{
	/*
	 * Alias ranks higher than no alias.
	 * (We want the new action to be used whenever possible.)
	 */
	if (!a_alias && b_alias)
		return -1;
	if (a_alias && !b_alias)
		return 1;

	/* Higher revision ranks higher. */
	if (a_rev < b_rev)
		return -1;
	if (a_rev > b_rev)
		return 1;

	/* NFPROTO_<specific> ranks higher than NFPROTO_UNSPEC. */
	if (a_fam == NFPROTO_UNSPEC && b_fam != NFPROTO_UNSPEC)
		return -1;
	if (a_fam != NFPROTO_UNSPEC && b_fam == NFPROTO_UNSPEC)
		return 1;

	/* Must be the same thing. */
	return 0;
}

static int xtables_match_prefer(const struct xtables_match *a,
				const struct xtables_match *b)
{
	return xtables_mt_prefer(a->real_name != NULL,
				 a->revision, a->family,
				 b->real_name != NULL,
				 b->revision, b->family);
}

static int xtables_target_prefer(const struct xtables_target *a,
				 const struct xtables_target *b)
{
	/*
	 * Note that if x->real_name==NULL, it will be set to x->name in
	 * xtables_register_*; the direct pointer comparison here is therefore
	 * legitimate to detect an alias.
	 */
	return xtables_mt_prefer(a->real_name != NULL,
				 a->revision, a->family,
				 b->real_name != NULL,
				 b->revision, b->family);
}

static bool xtables_fully_register_pending_match(struct xtables_match *me,
						 struct xtables_match *prev)
{
	struct xtables_match **i;
	const char *rn;

	/* See if new match can be used. */
	rn = (me->real_name != NULL) ? me->real_name : me->name;
	if (!compatible_match_revision(rn, me->revision))
		return false;

	if (!prev) {
		/* Append to list. */
		for (i = &xtables_matches; *i; i = &(*i)->next);
	} else {
		/* Append it */
		i = &prev->next;
		prev = prev->next;
	}

	me->next = prev;
	*i = me;

	me->m = NULL;
	me->mflags = 0;

	return true;
}

void xtables_register_matches(struct xtables_match *match, unsigned int n)
{
	int i;

	for (i = 0; i < n; i++)
		xtables_register_match(&match[i]);
}

void xtables_register_target(struct xtables_target *me)
{
	struct xtables_target **pos;
	bool seen_myself = false;

	if (me->next) {
		fprintf(stderr, "%s: target \"%s\" already registered\n",
			xt_params->program_name, me->name);
		exit(1);
	}

	if (me->version == NULL) {
		fprintf(stderr, "%s: target %s<%u> is missing a version\n",
		        xt_params->program_name, me->name, me->revision);
		exit(1);
	}

	if (me->size != XT_ALIGN(me->size)) {
		fprintf(stderr, "%s: target \"%s\" has invalid size %u.\n",
		        xt_params->program_name, me->name,
		        (unsigned int)me->size);
		exit(1);
	}

	if (strcmp(me->version, XTABLES_VERSION) != 0) {
		fprintf(stderr, "%s: target \"%s\" has version \"%s\", "
		        "but \"%s\" is required.\n",
			xt_params->program_name, me->name,
			me->version, XTABLES_VERSION);
		exit(1);
	}

	if (strlen(me->name) >= XT_EXTENSION_MAXNAMELEN) {
		fprintf(stderr, "%s: target `%s' has invalid name\n",
			xt_params->program_name, me->name);
		exit(1);
	}

	if (me->real_name && strlen(me->real_name) >= XT_EXTENSION_MAXNAMELEN) {
		fprintf(stderr, "%s: target `%s' has invalid real name\n",
			xt_params->program_name, me->real_name);
		exit(1);
	}

	if (me->family >= NPROTO) {
		fprintf(stderr,
			"%s: BUG: target %s has invalid protocol family\n",
			xt_params->program_name, me->name);
		exit(1);
	}

	if (me->x6_options != NULL)
		xtables_option_metavalidate(me->name, me->x6_options);
	if (me->extra_opts != NULL)
		xtables_check_options(me->name, me->extra_opts);

	/* ignore not interested target */
	if (me->family != afinfo->family && me->family != AF_UNSPEC)
		return;

	/* order into linked list of targets pending full registration */
	for (pos = &xtables_pending_targets; *pos; pos = &(*pos)->next) {
		/* group by name */
		if (!extension_cmp(me->name, (*pos)->name, (*pos)->family)) {
			if (seen_myself)
				break; /* end of own group, append to it */
			continue;
		}
		/* found own group */
		seen_myself = true;
		if (xtables_target_prefer(me, *pos) >= 0)
			break; /* put preferred items first in group */
	}
	/* if own group was not found, prepend item */
	if (!*pos && !seen_myself)
		pos = &xtables_pending_targets;

	me->next = *pos;
	*pos = me;
#ifdef DEBUG
	printf("%s: inserted target %s (family %d, revision %d):\n",
			__func__, me->name, me->family, me->revision);
	for (pos = &xtables_pending_targets; *pos; pos = &(*pos)->next) {
		printf("%s:\ttarget %s (family %d, revision %d)\n", __func__,
		       (*pos)->name, (*pos)->family, (*pos)->revision);
	}
#endif
}

static bool xtables_fully_register_pending_target(struct xtables_target *me,
						  struct xtables_target *prev)
{
	struct xtables_target **i;
	const char *rn;

	if (strcmp(me->name, "standard") != 0) {
		/* See if new target can be used. */
		rn = (me->real_name != NULL) ? me->real_name : me->name;
		if (!compatible_target_revision(rn, me->revision))
			return false;
	}

	if (!prev) {
		/* Prepend to list. */
		i = &xtables_targets;
		prev = xtables_targets;
	} else {
		/* Append it */
		i = &prev->next;
		prev = prev->next;
	}

	me->next = prev;
	*i = me;

	me->t = NULL;
	me->tflags = 0;

	return true;
}

void xtables_register_targets(struct xtables_target *target, unsigned int n)
{
	int i;

	for (i = 0; i < n; i++)
		xtables_register_target(&target[i]);
}

/* receives a list of xtables_rule_match, release them */
void xtables_rule_matches_free(struct xtables_rule_match **matches)
{
	struct xtables_rule_match *matchp, *tmp;

	for (matchp = *matches; matchp;) {
		tmp = matchp->next;
		if (matchp->match->m) {
			free(matchp->match->m);
			matchp->match->m = NULL;
		}
		if (matchp->match == matchp->match->next) {
			free(matchp->match);
			matchp->match = NULL;
		}
		free(matchp);
		matchp = tmp;
	}

	*matches = NULL;
}

/**
 * xtables_param_act - act on condition
 * @status:	a constant from enum xtables_exittype
 *
 * %XTF_ONLY_ONCE: print error message that option may only be used once.
 * @p1:		module name (e.g. "mark")
 * @p2(...):	option in conflict (e.g. "--mark")
 * @p3(...):	condition to match on (see extensions/ for examples)
 *
 * %XTF_NO_INVERT: option does not support inversion
 * @p1:		module name
 * @p2:		option in conflict
 * @p3:		condition to match on
 *
 * %XTF_BAD_VALUE: bad value for option
 * @p1:		module name
 * @p2:		option with which the problem occurred (e.g. "--mark")
 * @p3:		string the user passed in (e.g. "99999999999999")
 *
 * %XTF_ONE_ACTION: two mutually exclusive actions have been specified
 * @p1:		module name
 *
 * Displays an error message and exits the program.
 */
void xtables_param_act(unsigned int status, const char *p1, ...)
{
	const char *p2, *p3;
	va_list args;
	bool b;

	va_start(args, p1);

	switch (status) {
	case XTF_ONLY_ONCE:
		p2 = va_arg(args, const char *);
		b  = va_arg(args, unsigned int);
		if (!b) {
			va_end(args);
			return;
		}
		xt_params->exit_err(PARAMETER_PROBLEM,
		           "%s: \"%s\" option may only be specified once",
		           p1, p2);
		break;
	case XTF_NO_INVERT:
		p2 = va_arg(args, const char *);
		b  = va_arg(args, unsigned int);
		if (!b) {
			va_end(args);
			return;
		}
		xt_params->exit_err(PARAMETER_PROBLEM,
		           "%s: \"%s\" option cannot be inverted", p1, p2);
		break;
	case XTF_BAD_VALUE:
		p2 = va_arg(args, const char *);
		p3 = va_arg(args, const char *);
		xt_params->exit_err(PARAMETER_PROBLEM,
		           "%s: Bad value for \"%s\" option: \"%s\"",
		           p1, p2, p3);
		break;
	case XTF_ONE_ACTION:
		b = va_arg(args, unsigned int);
		if (!b) {
			va_end(args);
			return;
		}
		xt_params->exit_err(PARAMETER_PROBLEM,
		           "%s: At most one action is possible", p1);
		break;
	default:
		xt_params->exit_err(status, p1, args);
		break;
	}

	va_end(args);
}

const char *xtables_ipaddr_to_numeric(const struct in_addr *addrp)
{
	static char buf[16];
	const unsigned char *bytep = (const void *)&addrp->s_addr;

	sprintf(buf, "%u.%u.%u.%u", bytep[0], bytep[1], bytep[2], bytep[3]);
	return buf;
}

static const char *ipaddr_to_host(const struct in_addr *addr)
{
	static char hostname[NI_MAXHOST];
	struct sockaddr_in saddr = {
		.sin_family = AF_INET,
		.sin_addr = *addr,
	};
	int err;


	err = getnameinfo((const void *)&saddr, sizeof(struct sockaddr_in),
		       hostname, sizeof(hostname) - 1, NULL, 0, 0);
	if (err != 0)
		return NULL;

	return hostname;
}

static const char *ipaddr_to_network(const struct in_addr *addr)
{
	struct netent *net;

	if ((net = getnetbyaddr(ntohl(addr->s_addr), AF_INET)) != NULL)
		return net->n_name;

	return NULL;
}

const char *xtables_ipaddr_to_anyname(const struct in_addr *addr)
{
	const char *name;

	if ((name = ipaddr_to_host(addr)) != NULL ||
	    (name = ipaddr_to_network(addr)) != NULL)
		return name;

	return xtables_ipaddr_to_numeric(addr);
}

int xtables_ipmask_to_cidr(const struct in_addr *mask)
{
	uint32_t maskaddr, bits;
	int i;

	maskaddr = ntohl(mask->s_addr);

	for (i = 32, bits = (uint32_t)-1; i >= 0; i--, bits <<= 1) {
		if (bits == maskaddr)
			return i;
	}

	/* this mask cannot be converted to CIDR notation */
	return -1;
}

const char *xtables_ipmask_to_numeric(const struct in_addr *mask)
{
	static char buf[20];
	uint32_t cidr;

	cidr = xtables_ipmask_to_cidr(mask);
	if (cidr == (unsigned int)-1) {
		/* mask was not a decent combination of 1's and 0's */
		sprintf(buf, "/%s", xtables_ipaddr_to_numeric(mask));
		return buf;
	} else if (cidr == 32) {
		/* we don't want to see "/32" */
		return "";
	}

	sprintf(buf, "/%d", cidr);
	return buf;
}

static struct in_addr *__numeric_to_ipaddr(const char *dotted, bool is_mask)
{
	static struct in_addr addr;
	unsigned char *addrp;
	unsigned int onebyte;
	char buf[20], *p, *q;
	int i;

	/* copy dotted string, because we need to modify it */
	strncpy(buf, dotted, sizeof(buf) - 1);
	buf[sizeof(buf) - 1] = '\0';
	addrp = (void *)&addr.s_addr;

	p = buf;
	for (i = 0; i < 3; ++i) {
		if ((q = strchr(p, '.')) == NULL) {
			if (is_mask)
				return NULL;

			/* autocomplete, this is a network address */
			if (!xtables_strtoui(p, NULL, &onebyte, 0, UINT8_MAX))
				return NULL;

			addrp[i] = onebyte;
			while (i < 3)
				addrp[++i] = 0;

			return &addr;
		}

		*q = '\0';
		if (!xtables_strtoui(p, NULL, &onebyte, 0, UINT8_MAX))
			return NULL;

		addrp[i] = onebyte;
		p = q + 1;
	}

	/* we have checked 3 bytes, now we check the last one */
	if (!xtables_strtoui(p, NULL, &onebyte, 0, UINT8_MAX))
		return NULL;

	addrp[3] = onebyte;
	return &addr;
}

struct in_addr *xtables_numeric_to_ipaddr(const char *dotted)
{
	return __numeric_to_ipaddr(dotted, false);
}

struct in_addr *xtables_numeric_to_ipmask(const char *dotted)
{
	return __numeric_to_ipaddr(dotted, true);
}

static struct in_addr *network_to_ipaddr(const char *name)
{
	static struct in_addr addr;
	struct netent *net;

	if ((net = getnetbyname(name)) != NULL) {
		if (net->n_addrtype != AF_INET)
			return NULL;
		addr.s_addr = htonl(net->n_net);
		return &addr;
	}

	return NULL;
}

static struct in_addr *host_to_ipaddr(const char *name, unsigned int *naddr)
{
	struct in_addr *addr;
	struct addrinfo hints;
	struct addrinfo *res, *p;
	int err;
	unsigned int i;

	memset(&hints, 0, sizeof(hints));
	hints.ai_family   = AF_INET;
	hints.ai_socktype = SOCK_RAW;

	*naddr = 0;
	err = getaddrinfo(name, NULL, &hints, &res);
	if (err != 0)
		return NULL;
	for (p = res; p != NULL; p = p->ai_next)
		++*naddr;
	addr = xtables_calloc(*naddr, sizeof(struct in_addr));
	for (i = 0, p = res; p != NULL; p = p->ai_next)
		memcpy(&addr[i++],
		       &((const struct sockaddr_in *)p->ai_addr)->sin_addr,
		       sizeof(struct in_addr));
	freeaddrinfo(res);
	return addr;
}

static struct in_addr *
ipparse_hostnetwork(const char *name, unsigned int *naddrs)
{
	struct in_addr *addrptmp, *addrp;

	if ((addrptmp = xtables_numeric_to_ipaddr(name)) != NULL ||
	    (addrptmp = network_to_ipaddr(name)) != NULL) {
		addrp = xtables_malloc(sizeof(struct in_addr));
		memcpy(addrp, addrptmp, sizeof(*addrp));
		*naddrs = 1;
		return addrp;
	}
	if ((addrptmp = host_to_ipaddr(name, naddrs)) != NULL)
		return addrptmp;

	xt_params->exit_err(PARAMETER_PROBLEM, "host/network `%s' not found", name);
}

static struct in_addr *parse_ipmask(const char *mask)
{
	static struct in_addr maskaddr;
	struct in_addr *addrp;
	unsigned int bits;

	if (mask == NULL) {
		/* no mask at all defaults to 32 bits */
		maskaddr.s_addr = 0xFFFFFFFF;
		return &maskaddr;
	}
	if ((addrp = xtables_numeric_to_ipmask(mask)) != NULL)
		/* dotted_to_addr already returns a network byte order addr */
		return addrp;
	if (!xtables_strtoui(mask, NULL, &bits, 0, 32))
		xt_params->exit_err(PARAMETER_PROBLEM,
			   "invalid mask `%s' specified", mask);
	if (bits != 0) {
		maskaddr.s_addr = htonl(0xFFFFFFFF << (32 - bits));
		return &maskaddr;
	}

	maskaddr.s_addr = 0U;
	return &maskaddr;
}

void xtables_ipparse_multiple(const char *name, struct in_addr **addrpp,
                              struct in_addr **maskpp, unsigned int *naddrs)
{
	struct in_addr *addrp;
	char buf[256], *p, *next;
	unsigned int len, i, j, n, count = 1;
	const char *loop = name;

	while ((loop = strchr(loop, ',')) != NULL) {
		++count;
		++loop; /* skip ',' */
	}

	*addrpp = xtables_malloc(sizeof(struct in_addr) * count);
	*maskpp = xtables_malloc(sizeof(struct in_addr) * count);

	loop = name;

	for (i = 0; i < count; ++i) {
		while (isspace(*loop))
			++loop;
		next = strchr(loop, ',');
		if (next != NULL)
			len = next - loop;
		else
			len = strlen(loop);
		if (len > sizeof(buf) - 1)
			xt_params->exit_err(PARAMETER_PROBLEM,
				"Hostname too long");

		strncpy(buf, loop, len);
		buf[len] = '\0';
		if ((p = strrchr(buf, '/')) != NULL) {
			*p = '\0';
			addrp = parse_ipmask(p + 1);
		} else {
			addrp = parse_ipmask(NULL);
		}
		memcpy(*maskpp + i, addrp, sizeof(*addrp));

		/* if a null mask is given, the name is ignored, like in "any/0" */
		if ((*maskpp + i)->s_addr == 0)
			/*
			 * A bit pointless to process multiple addresses
			 * in this case...
			 */
			strcpy(buf, "0.0.0.0");

		addrp = ipparse_hostnetwork(buf, &n);
		if (n > 1) {
			count += n - 1;
			*addrpp = xtables_realloc(*addrpp,
			          sizeof(struct in_addr) * count);
			*maskpp = xtables_realloc(*maskpp,
			          sizeof(struct in_addr) * count);
			for (j = 0; j < n; ++j)
				/* for each new addr */
				memcpy(*addrpp + i + j, addrp + j,
				       sizeof(*addrp));
			for (j = 1; j < n; ++j)
				/* for each new mask */
				memcpy(*maskpp + i + j, *maskpp + i,
				       sizeof(*addrp));
			i += n - 1;
		} else {
			memcpy(*addrpp + i, addrp, sizeof(*addrp));
		}
		/* free what ipparse_hostnetwork had allocated: */
		free(addrp);
		if (next == NULL)
			break;
		loop = next + 1;
	}
	*naddrs = count;
	for (i = 0; i < count; ++i)
		(*addrpp+i)->s_addr &= (*maskpp+i)->s_addr;
}


/**
 * xtables_ipparse_any - transform arbitrary name to in_addr
 *
 * Possible inputs (pseudo regex):
 * 	m{^($hostname|$networkname|$ipaddr)(/$mask)?}
 * "1.2.3.4/5", "1.2.3.4", "hostname", "networkname"
 */
void xtables_ipparse_any(const char *name, struct in_addr **addrpp,
                         struct in_addr *maskp, unsigned int *naddrs)
{
	unsigned int i, j, k, n;
	struct in_addr *addrp;
	char buf[256], *p;

	strncpy(buf, name, sizeof(buf) - 1);
	buf[sizeof(buf) - 1] = '\0';
	if ((p = strrchr(buf, '/')) != NULL) {
		*p = '\0';
		addrp = parse_ipmask(p + 1);
	} else {
		addrp = parse_ipmask(NULL);
	}
	memcpy(maskp, addrp, sizeof(*maskp));

	/* if a null mask is given, the name is ignored, like in "any/0" */
	if (maskp->s_addr == 0U)
		strcpy(buf, "0.0.0.0");

	addrp = *addrpp = ipparse_hostnetwork(buf, naddrs);
	n = *naddrs;
	for (i = 0, j = 0; i < n; ++i) {
		addrp[j++].s_addr &= maskp->s_addr;
		for (k = 0; k < j - 1; ++k)
			if (addrp[k].s_addr == addrp[j-1].s_addr) {
				/*
				 * Nuke the dup by copying an address from the
				 * tail here, and check the current position
				 * again (--j).
				 */
				memcpy(&addrp[--j], &addrp[--*naddrs],
				       sizeof(struct in_addr));
				break;
			}
	}
}

const char *xtables_ip6addr_to_numeric(const struct in6_addr *addrp)
{
	/* 0000:0000:0000:0000:0000:0000:000.000.000.000
	 * 0000:0000:0000:0000:0000:0000:0000:0000 */
	static char buf[50+1];
	return inet_ntop(AF_INET6, addrp, buf, sizeof(buf));
}

static const char *ip6addr_to_host(const struct in6_addr *addr)
{
	static char hostname[NI_MAXHOST];
	struct sockaddr_in6 saddr;
	int err;

	memset(&saddr, 0, sizeof(struct sockaddr_in6));
	memcpy(&saddr.sin6_addr, addr, sizeof(*addr));
	saddr.sin6_family = AF_INET6;

	err = getnameinfo((const void *)&saddr, sizeof(struct sockaddr_in6),
			hostname, sizeof(hostname) - 1, NULL, 0, 0);
	if (err != 0)
		return NULL;

	return hostname;
}

const char *xtables_ip6addr_to_anyname(const struct in6_addr *addr)
{
	const char *name;

	if ((name = ip6addr_to_host(addr)) != NULL)
		return name;

	return xtables_ip6addr_to_numeric(addr);
}

int xtables_ip6mask_to_cidr(const struct in6_addr *k)
{
	unsigned int bits = 0;
	uint32_t a, b, c, d;

	a = ntohl(k->s6_addr32[0]);
	b = ntohl(k->s6_addr32[1]);
	c = ntohl(k->s6_addr32[2]);
	d = ntohl(k->s6_addr32[3]);
	while (a & 0x80000000U) {
		++bits;
		a <<= 1;
		a  |= (b >> 31) & 1;
		b <<= 1;
		b  |= (c >> 31) & 1;
		c <<= 1;
		c  |= (d >> 31) & 1;
		d <<= 1;
	}
	if (a != 0 || b != 0 || c != 0 || d != 0)
		return -1;
	return bits;
}

const char *xtables_ip6mask_to_numeric(const struct in6_addr *addrp)
{
	static char buf[50+2];
	int l = xtables_ip6mask_to_cidr(addrp);

	if (l == -1) {
		strcpy(buf, "/");
		strcat(buf, xtables_ip6addr_to_numeric(addrp));
		return buf;
	}
	/* we don't want to see "/128" */
	if (l == 128)
		return "";
	else
		sprintf(buf, "/%d", l);
	return buf;
}

struct in6_addr *xtables_numeric_to_ip6addr(const char *num)
{
	static struct in6_addr ap;

	if (inet_pton(AF_INET6, num, &ap) == 1)
		return &ap;

	return NULL;
}

static struct in6_addr *
host_to_ip6addr(const char *name, unsigned int *naddr)
{
	struct in6_addr *addr;
	struct addrinfo hints;
	struct addrinfo *res, *p;
	int err;
	unsigned int i;

	memset(&hints, 0, sizeof(hints));
	hints.ai_family   = AF_INET6;
	hints.ai_socktype = SOCK_RAW;

	*naddr = 0;
	err = getaddrinfo(name, NULL, &hints, &res);
	if (err != 0)
		return NULL;
	/* Find length of address chain */
	for (p = res; p != NULL; p = p->ai_next)
		++*naddr;
	/* Copy each element of the address chain */
	addr = xtables_calloc(*naddr, sizeof(struct in6_addr));
	for (i = 0, p = res; p != NULL; p = p->ai_next)
		memcpy(&addr[i++],
		       &((const struct sockaddr_in6 *)p->ai_addr)->sin6_addr,
		       sizeof(struct in6_addr));
	freeaddrinfo(res);
	return addr;
}

static struct in6_addr *network_to_ip6addr(const char *name)
{
	/*	abort();*/
	/* TODO: not implemented yet, but the exception breaks the
	 *       name resolvation */
	return NULL;
}

static struct in6_addr *
ip6parse_hostnetwork(const char *name, unsigned int *naddrs)
{
	struct in6_addr *addrp, *addrptmp;

	if ((addrptmp = xtables_numeric_to_ip6addr(name)) != NULL ||
	    (addrptmp = network_to_ip6addr(name)) != NULL) {
		addrp = xtables_malloc(sizeof(struct in6_addr));
		memcpy(addrp, addrptmp, sizeof(*addrp));
		*naddrs = 1;
		return addrp;
	}
	if ((addrp = host_to_ip6addr(name, naddrs)) != NULL)
		return addrp;

	xt_params->exit_err(PARAMETER_PROBLEM, "host/network `%s' not found", name);
}

static struct in6_addr *parse_ip6mask(char *mask)
{
	static struct in6_addr maskaddr;
	struct in6_addr *addrp;
	unsigned int bits;

	if (mask == NULL) {
		/* no mask at all defaults to 128 bits */
		memset(&maskaddr, 0xff, sizeof maskaddr);
		return &maskaddr;
	}
	if ((addrp = xtables_numeric_to_ip6addr(mask)) != NULL)
		return addrp;
	if (!xtables_strtoui(mask, NULL, &bits, 0, 128))
		xt_params->exit_err(PARAMETER_PROBLEM,
			   "invalid mask `%s' specified", mask);
	if (bits != 0) {
		char *p = (void *)&maskaddr;
		memset(p, 0xff, bits / 8);
		memset(p + ((bits + 7) / 8), 0, (128 - bits) / 8);
		if (bits < 128)
			p[bits/8] = 0xff << (8 - (bits & 7));
		return &maskaddr;
	}

	memset(&maskaddr, 0, sizeof(maskaddr));
	return &maskaddr;
}

void
xtables_ip6parse_multiple(const char *name, struct in6_addr **addrpp,
		      struct in6_addr **maskpp, unsigned int *naddrs)
{
	static const struct in6_addr zero_addr;
	struct in6_addr *addrp;
	char buf[256], *p, *next;
	unsigned int len, i, j, n, count = 1;
	const char *loop = name;

	while ((loop = strchr(loop, ',')) != NULL) {
		++count;
		++loop; /* skip ',' */
	}

	*addrpp = xtables_malloc(sizeof(struct in6_addr) * count);
	*maskpp = xtables_malloc(sizeof(struct in6_addr) * count);

	loop = name;

	for (i = 0; i < count /*NB: count can grow*/; ++i) {
		while (isspace(*loop))
			++loop;
		next = strchr(loop, ',');
		if (next != NULL)
			len = next - loop;
		else
			len = strlen(loop);
		if (len > sizeof(buf) - 1)
			xt_params->exit_err(PARAMETER_PROBLEM,
				"Hostname too long");

		strncpy(buf, loop, len);
		buf[len] = '\0';
		if ((p = strrchr(buf, '/')) != NULL) {
			*p = '\0';
			addrp = parse_ip6mask(p + 1);
		} else {
			addrp = parse_ip6mask(NULL);
		}
		memcpy(*maskpp + i, addrp, sizeof(*addrp));

		/* if a null mask is given, the name is ignored, like in "any/0" */
		if (memcmp(*maskpp + i, &zero_addr, sizeof(zero_addr)) == 0)
			strcpy(buf, "::");

		addrp = ip6parse_hostnetwork(buf, &n);
		if (n > 1) {
			count += n - 1;
			*addrpp = xtables_realloc(*addrpp,
			          sizeof(struct in6_addr) * count);
			*maskpp = xtables_realloc(*maskpp,
			          sizeof(struct in6_addr) * count);
			for (j = 0; j < n; ++j)
				/* for each new addr */
				memcpy(*addrpp + i + j, addrp + j,
				       sizeof(*addrp));
			for (j = 1; j < n; ++j)
				/* for each new mask */
				memcpy(*maskpp + i + j, *maskpp + i,
				       sizeof(*addrp));
			i += n - 1;
		} else {
			memcpy(*addrpp + i, addrp, sizeof(*addrp));
		}
		/* free what ip6parse_hostnetwork had allocated: */
		free(addrp);
		if (next == NULL)
			break;
		loop = next + 1;
	}
	*naddrs = count;
	for (i = 0; i < count; ++i)
		for (j = 0; j < 4; ++j)
			(*addrpp+i)->s6_addr32[j] &= (*maskpp+i)->s6_addr32[j];
}

void xtables_ip6parse_any(const char *name, struct in6_addr **addrpp,
                          struct in6_addr *maskp, unsigned int *naddrs)
{
	static const struct in6_addr zero_addr;
	struct in6_addr *addrp;
	unsigned int i, j, k, n;
	char buf[256], *p;

	strncpy(buf, name, sizeof(buf) - 1);
	buf[sizeof(buf)-1] = '\0';
	if ((p = strrchr(buf, '/')) != NULL) {
		*p = '\0';
		addrp = parse_ip6mask(p + 1);
	} else {
		addrp = parse_ip6mask(NULL);
	}
	memcpy(maskp, addrp, sizeof(*maskp));

	/* if a null mask is given, the name is ignored, like in "any/0" */
	if (memcmp(maskp, &zero_addr, sizeof(zero_addr)) == 0)
		strcpy(buf, "::");

	addrp = *addrpp = ip6parse_hostnetwork(buf, naddrs);
	n = *naddrs;
	for (i = 0, j = 0; i < n; ++i) {
		for (k = 0; k < 4; ++k)
			addrp[j].s6_addr32[k] &= maskp->s6_addr32[k];
		++j;
		for (k = 0; k < j - 1; ++k)
			if (IN6_ARE_ADDR_EQUAL(&addrp[k], &addrp[j - 1])) {
				/*
				 * Nuke the dup by copying an address from the
				 * tail here, and check the current position
				 * again (--j).
				 */
				memcpy(&addrp[--j], &addrp[--*naddrs],
				       sizeof(struct in_addr));
				break;
			}
	}
}

void xtables_save_string(const char *value)
{
	static const char no_quote_chars[] = "_-0123456789"
		"abcdefghijklmnopqrstuvwxyz"
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	static const char escape_chars[] = "\"\\'";
	size_t length;
	const char *p;

	length = strspn(value, no_quote_chars);
	if (length > 0 && value[length] == 0) {
		/* no quoting required */
		putchar(' ');
		fputs(value, stdout);
	} else {
		/* there is at least one dangerous character in the
		   value, which we have to quote.  Write double quotes
		   around the value and escape special characters with
		   a backslash */
		printf(" \"");

		for (p = strpbrk(value, escape_chars); p != NULL;
		     p = strpbrk(value, escape_chars)) {
			if (p > value)
				fwrite(value, 1, p - value, stdout);
			putchar('\\');
			putchar(*p);
			value = p + 1;
		}

		/* print the rest and finish the double quoted
		   string */
		fputs(value, stdout);
		putchar('\"');
	}
}

const struct xtables_pprot xtables_chain_protos[] = {
	{"tcp",       IPPROTO_TCP},
	{"sctp",      IPPROTO_SCTP},
	{"udp",       IPPROTO_UDP},
	{"udplite",   IPPROTO_UDPLITE},
	{"icmp",      IPPROTO_ICMP},
	{"ipv6-icmp", IPPROTO_ICMPV6},
	{"icmpv6",    IPPROTO_ICMPV6},
	{"esp",       IPPROTO_ESP},
	{"ah",        IPPROTO_AH},
	{"mobility-header", IPPROTO_MH},
	{"ipv6-mh",   IPPROTO_MH},
	{"mh",        IPPROTO_MH},
	{"all",       0},
	{NULL},
};

uint16_t
xtables_parse_protocol(const char *s)
{
	const struct protoent *pent;
	unsigned int proto, i;

	if (xtables_strtoui(s, NULL, &proto, 0, UINT8_MAX))
		return proto;

	for (i = 0; xtables_chain_protos[i].name != NULL; ++i) {
		if (strcmp(s, xtables_chain_protos[i].name) == 0)
			return xtables_chain_protos[i].num;
	}

	pent = getprotobyname(s);
	if (pent != NULL)
		return pent->p_proto;

	xt_params->exit_err(PARAMETER_PROBLEM,
		"unknown protocol \"%s\" specified", s);
	return -1;
}

void xtables_print_num(uint64_t number, unsigned int format)
{
	if (!(format & FMT_KILOMEGAGIGA)) {
		printf(FMT("%8llu ","%llu "), (unsigned long long)number);
		return;
	}
	if (number <= 99999) {
		printf(FMT("%5llu ","%llu "), (unsigned long long)number);
		return;
	}
	number = (number + 500) / 1000;
	if (number <= 9999) {
		printf(FMT("%4lluK ","%lluK "), (unsigned long long)number);
		return;
	}
	number = (number + 500) / 1000;
	if (number <= 9999) {
		printf(FMT("%4lluM ","%lluM "), (unsigned long long)number);
		return;
	}
	number = (number + 500) / 1000;
	if (number <= 9999) {
		printf(FMT("%4lluG ","%lluG "), (unsigned long long)number);
		return;
	}
	number = (number + 500) / 1000;
	printf(FMT("%4lluT ","%lluT "), (unsigned long long)number);
}

static const unsigned char mac_type_unicast[ETH_ALEN] =   {};
static const unsigned char msk_type_unicast[ETH_ALEN] =   {1};
static const unsigned char mac_type_multicast[ETH_ALEN] = {1};
static const unsigned char msk_type_multicast[ETH_ALEN] = {1};
#define ALL_ONE_MAC {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
static const unsigned char mac_type_broadcast[ETH_ALEN] = ALL_ONE_MAC;
static const unsigned char msk_type_broadcast[ETH_ALEN] = ALL_ONE_MAC;
static const unsigned char mac_type_bridge_group[ETH_ALEN] = {0x01, 0x80, 0xc2};
static const unsigned char msk_type_bridge_group[ETH_ALEN] = ALL_ONE_MAC;
#undef ALL_ONE_MAC

int xtables_parse_mac_and_mask(const char *from, void *to, void *mask)
{
	char *p;
	int i;
	struct ether_addr *addr = NULL;

	if (strcasecmp(from, "Unicast") == 0) {
		memcpy(to, mac_type_unicast, ETH_ALEN);
		memcpy(mask, msk_type_unicast, ETH_ALEN);
		return 0;
	}
	if (strcasecmp(from, "Multicast") == 0) {
		memcpy(to, mac_type_multicast, ETH_ALEN);
		memcpy(mask, msk_type_multicast, ETH_ALEN);
		return 0;
	}
	if (strcasecmp(from, "Broadcast") == 0) {
		memcpy(to, mac_type_broadcast, ETH_ALEN);
		memcpy(mask, msk_type_broadcast, ETH_ALEN);
		return 0;
	}
	if (strcasecmp(from, "BGA") == 0) {
		memcpy(to, mac_type_bridge_group, ETH_ALEN);
		memcpy(mask, msk_type_bridge_group, ETH_ALEN);
		return 0;
	}
	if ( (p = strrchr(from, '/')) != NULL) {
		*p = '\0';
		if (!(addr = ether_aton(p + 1)))
			return -1;
		memcpy(mask, addr, ETH_ALEN);
	} else
		memset(mask, 0xff, ETH_ALEN);
	if (!(addr = ether_aton(from)))
		return -1;
	memcpy(to, addr, ETH_ALEN);
	for (i = 0; i < ETH_ALEN; i++)
		((char *)to)[i] &= ((char *)mask)[i];
	return 0;
}

int xtables_print_well_known_mac_and_mask(const void *mac, const void *mask)
{
	if (!memcmp(mac, mac_type_unicast, ETH_ALEN) &&
	    !memcmp(mask, msk_type_unicast, ETH_ALEN))
		printf("Unicast");
	else if (!memcmp(mac, mac_type_multicast, ETH_ALEN) &&
	         !memcmp(mask, msk_type_multicast, ETH_ALEN))
		printf("Multicast");
	else if (!memcmp(mac, mac_type_broadcast, ETH_ALEN) &&
	         !memcmp(mask, msk_type_broadcast, ETH_ALEN))
		printf("Broadcast");
	else if (!memcmp(mac, mac_type_bridge_group, ETH_ALEN) &&
	         !memcmp(mask, msk_type_bridge_group, ETH_ALEN))
		printf("BGA");
	else
		return -1;
	return 0;
}

void xtables_print_mac(const unsigned char *macaddress)
{
	unsigned int i;

	printf("%02x", macaddress[0]);
	for (i = 1; i < 6; ++i)
		printf(":%02x", macaddress[i]);
}

void xtables_print_mac_and_mask(const unsigned char *mac, const unsigned char *mask)
{
	static const char hlpmsk[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

	xtables_print_mac(mac);

	if (memcmp(mask, hlpmsk, 6) == 0)
		return;

	printf("/");
	xtables_print_mac(mask);
}

void xtables_parse_val_mask(struct xt_option_call *cb,
			    unsigned int *val, unsigned int *mask,
			    const struct xtables_lmap *lmap)
{
	char *end;

	*mask = ~0U;

	if (!xtables_strtoui(cb->arg, &end, val, 0, UINT32_MAX)) {
		if (lmap)
			goto name2val;
		else
			goto bad_val;
	}

	if (*end == '\0')
		return;

	if (*end != '/') {
		if (lmap)
			goto name2val;
		else
			goto garbage;
	}

	if (!xtables_strtoui(end + 1, &end, mask, 0, UINT32_MAX))
		goto bad_val;

	if (*end == '\0')
		return;

garbage:
	xt_params->exit_err(PARAMETER_PROBLEM,
			"%s: trailing garbage after value "
			"for option \"--%s\".\n",
			cb->ext_name, cb->entry->name);

bad_val:
	xt_params->exit_err(PARAMETER_PROBLEM,
			"%s: bad integer value for option \"--%s\", "
			"or out of range.\n",
			cb->ext_name, cb->entry->name);

name2val:
	*val = xtables_lmap_name2id(lmap, cb->arg);
	if ((int)*val == -1)
		xt_params->exit_err(PARAMETER_PROBLEM,
			"%s: could not map name %s to an integer value "
			"for option \"--%s\".\n",
			cb->ext_name, cb->arg, cb->entry->name);
}

void xtables_print_val_mask(unsigned int val, unsigned int mask,
			    const struct xtables_lmap *lmap)
{
	if (mask != ~0U) {
		printf(" 0x%x/0x%x", val, mask);
		return;
	}

	if (lmap) {
		const char *name = xtables_lmap_id2name(lmap, val);

		if (name) {
			printf(" %s", name);
			return;
		}
	}

	printf(" 0x%x", val);
}

int kernel_version;

void get_kernel_version(void)
{
	static struct utsname uts;
	int x = 0, y = 0, z = 0;

	if (uname(&uts) == -1) {
		fprintf(stderr, "Unable to retrieve kernel version.\n");
		xtables_free_opts(1);
		exit(1);
	}

	sscanf(uts.release, "%d.%d.%d", &x, &y, &z);
	kernel_version = LINUX_VERSION(x, y, z);
}

#include <linux/netfilter/nf_tables.h>

enum xt_xlate_type {
	XT_XLATE_RULE = 0,
	XT_XLATE_SET,
	__XT_XLATE_MAX
};

struct xt_xlate {
	struct xt_xlate_buf {
		char	*data;
		int	size;
		int	rem;
		int	off;
	} buf[__XT_XLATE_MAX];
	char comment[NFT_USERDATA_MAXLEN];
	int family;
};

struct xt_xlate *xt_xlate_alloc(int size)
{
	struct xt_xlate *xl = xtables_malloc(sizeof(struct xt_xlate));
	int i;

	for (i = 0; i < __XT_XLATE_MAX; i++) {
		xl->buf[i].data = xtables_malloc(size);
		xl->buf[i].data[0] = '\0';
		xl->buf[i].size = size;
		xl->buf[i].rem = size;
		xl->buf[i].off = 0;
	}
	xl->comment[0] = '\0';

	return xl;
}

void xt_xlate_free(struct xt_xlate *xl)
{
	int i;

	for (i = 0; i < __XT_XLATE_MAX; i++)
		free(xl->buf[i].data);

	free(xl);
}

static bool isbrace(char c)
{
	switch (c) {
	case '(':
	case ')':
	case '{':
	case '}':
	case '[':
	case ']':
		return true;
	}
	return false;
}

static void __xt_xlate_add(struct xt_xlate *xl, enum xt_xlate_type type,
			   bool space, const char *fmt, va_list ap)
{
	struct xt_xlate_buf *buf = &xl->buf[type];
	char tmpbuf[1024] = "";
	int len;

	len = vsnprintf(tmpbuf, 1024, fmt, ap);
	if (len < 0 || len >= buf->rem - 1)
		xtables_error(RESOURCE_PROBLEM, "OOM");

	if (space && buf->off &&
	    !isspace(buf->data[buf->off - 1]) &&
	    (isalnum(tmpbuf[0]) || isbrace(tmpbuf[0]))) {
		buf->data[buf->off] = ' ';
		buf->off++;
		buf->rem--;
	}
	sprintf(buf->data + buf->off, "%s", tmpbuf);
	buf->rem -= len;
	buf->off += len;
}

void xt_xlate_rule_add(struct xt_xlate *xl, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__xt_xlate_add(xl, XT_XLATE_RULE, true, fmt, ap);
	va_end(ap);
}

void xt_xlate_rule_add_nospc(struct xt_xlate *xl, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__xt_xlate_add(xl, XT_XLATE_RULE, false, fmt, ap);
	va_end(ap);
}

void xt_xlate_set_add(struct xt_xlate *xl, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__xt_xlate_add(xl, XT_XLATE_SET, true, fmt, ap);
	va_end(ap);
}

void xt_xlate_set_add_nospc(struct xt_xlate *xl, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	__xt_xlate_add(xl, XT_XLATE_SET, false, fmt, ap);
	va_end(ap);
}

void xt_xlate_add_comment(struct xt_xlate *xl, const char *comment)
{
	strncpy(xl->comment, comment, NFT_USERDATA_MAXLEN - 1);
	xl->comment[NFT_USERDATA_MAXLEN - 1] = '\0';
}

const char *xt_xlate_get_comment(struct xt_xlate *xl)
{
	return xl->comment[0] ? xl->comment : NULL;
}

void xl_xlate_set_family(struct xt_xlate *xl, uint8_t family)
{
	xl->family = family;
}

uint8_t xt_xlate_get_family(struct xt_xlate *xl)
{
	return xl->family;
}

const char *xt_xlate_get(struct xt_xlate *xl)
{
	struct xt_xlate_buf *buf = &xl->buf[XT_XLATE_RULE];

	while (buf->off && isspace(buf->data[buf->off - 1]))
		buf->data[--buf->off] = '\0';

	return buf->data;
}

const char *xt_xlate_set_get(struct xt_xlate *xl)
{
	return xl->buf[XT_XLATE_SET].data;
}