summaryrefslogtreecommitdiff
path: root/ext/socket/raddrinfo.c
blob: 3eb92dabb9669f21a7e68797230b9dfa4fb8c232 (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
/************************************************

  ainfo.c -

  created at: Thu Mar 31 12:21:29 JST 1994

  Copyright (C) 1993-2007 Yukihiro Matsumoto

************************************************/

#include "rubysocket.h"

#if defined(INET6) && (defined(LOOKUP_ORDER_HACK_INET) || defined(LOOKUP_ORDER_HACK_INET6))
#define LOOKUP_ORDERS (sizeof(lookup_order_table) / sizeof(lookup_order_table[0]))
static const int lookup_order_table[] = {
#if defined(LOOKUP_ORDER_HACK_INET)
    PF_INET, PF_INET6, PF_UNSPEC,
#elif defined(LOOKUP_ORDER_HACK_INET6)
    PF_INET6, PF_INET, PF_UNSPEC,
#else
    /* should not happen */
#endif
};

static int
ruby_getaddrinfo(const char *nodename, const char *servname,
		 const struct addrinfo *hints, struct addrinfo **res)
{
    struct addrinfo tmp_hints;
    int i, af, error;

    if (hints->ai_family != PF_UNSPEC) {
	return getaddrinfo(nodename, servname, hints, res);
    }

    for (i = 0; i < LOOKUP_ORDERS; i++) {
	af = lookup_order_table[i];
	MEMCPY(&tmp_hints, hints, struct addrinfo, 1);
	tmp_hints.ai_family = af;
	error = getaddrinfo(nodename, servname, &tmp_hints, res);
	if (error) {
	    if (tmp_hints.ai_family == PF_UNSPEC) {
		break;
	    }
	}
	else {
	    break;
	}
    }

    return error;
}
#define getaddrinfo(node,serv,hints,res) ruby_getaddrinfo((node),(serv),(hints),(res))
#endif

#if defined(_AIX)
static int
ruby_getaddrinfo__aix(const char *nodename, const char *servname,
		      const struct addrinfo *hints, struct addrinfo **res)
{
    int error = getaddrinfo(nodename, servname, hints, res);
    struct addrinfo *r;
    if (error)
	return error;
    for (r = *res; r != NULL; r = r->ai_next) {
	if (r->ai_addr->sa_family == 0)
	    r->ai_addr->sa_family = r->ai_family;
	if (r->ai_addr->sa_len == 0)
	    r->ai_addr->sa_len = r->ai_addrlen;
    }
    return 0;
}
#undef getaddrinfo
#define getaddrinfo(node,serv,hints,res) ruby_getaddrinfo__aix((node),(serv),(hints),(res))
static int
ruby_getnameinfo__aix(const struct sockaddr *sa, size_t salen,
		      char *host, size_t hostlen,
		      char *serv, size_t servlen, int flags)
{
    struct sockaddr_in6 *sa6;
    u_int32_t *a6;

    if (sa->sa_family == AF_INET6) {
	sa6 = (struct sockaddr_in6 *)sa;
	a6 = sa6->sin6_addr.u6_addr.u6_addr32;

	if (a6[0] == 0 && a6[1] == 0 && a6[2] == 0 && a6[3] == 0) {
	    strncpy(host, "::", hostlen);
	    snprintf(serv, servlen, "%d", sa6->sin6_port);
	    return 0;
	}
    }
    return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
}
#undef getnameinfo
#define getnameinfo(sa, salen, host, hostlen, serv, servlen, flags) \
            ruby_getnameinfo__aix((sa), (salen), (host), (hostlen), (serv), (servlen), (flags))
#endif

static int str_is_number(const char *);

#if defined(__APPLE__)
static int
ruby_getaddrinfo__darwin(const char *nodename, const char *servname,
			 const struct addrinfo *hints, struct addrinfo **res)
{
    /* fix [ruby-core:29427] */
    const char *tmp_servname;
    struct addrinfo tmp_hints;
    int error;

    tmp_servname = servname;
    MEMCPY(&tmp_hints, hints, struct addrinfo, 1);
    if (nodename && servname) {
	if (str_is_number(tmp_servname) && atoi(servname) == 0) {
	    tmp_servname = NULL;
#ifdef AI_NUMERICSERV
	    if (tmp_hints.ai_flags) tmp_hints.ai_flags &= ~AI_NUMERICSERV;
#endif
	}
    }

    error = getaddrinfo(nodename, tmp_servname, &tmp_hints, res);
    if (error == 0) {
        /* [ruby-dev:23164] */
        struct addrinfo *r;
        r = *res;
        while (r) {
            if (! r->ai_socktype) r->ai_socktype = hints->ai_socktype;
            if (! r->ai_protocol) {
                if (r->ai_socktype == SOCK_DGRAM) {
                    r->ai_protocol = IPPROTO_UDP;
                }
                else if (r->ai_socktype == SOCK_STREAM) {
                    r->ai_protocol = IPPROTO_TCP;
                }
            }
            r = r->ai_next;
        }
    }

    return error;
}
#undef getaddrinfo
#define getaddrinfo(node,serv,hints,res) ruby_getaddrinfo__darwin((node),(serv),(hints),(res))
#endif

#ifndef GETADDRINFO_EMU
struct getaddrinfo_arg
{
    const char *node;
    const char *service;
    const struct addrinfo *hints;
    struct addrinfo **res;
};

static void *
nogvl_getaddrinfo(void *arg)
{
    int ret;
    struct getaddrinfo_arg *ptr = arg;
    ret = getaddrinfo(ptr->node, ptr->service, ptr->hints, ptr->res);
#ifdef __linux__
    /* On Linux (mainly Ubuntu 13.04) /etc/nsswitch.conf has mdns4 and
     * it cause getaddrinfo to return EAI_SYSTEM/ENOENT. [ruby-list:49420]
     */
    if (ret == EAI_SYSTEM && errno == ENOENT)
	ret = EAI_NONAME;
#endif
    return (void *)(VALUE)ret;
}
#endif

static int
numeric_getaddrinfo(const char *node, const char *service,
        const struct addrinfo *hints,
        struct addrinfo **res)
{
    static const struct {
        int socktype;
        int protocol;
    } list[] = {
        { SOCK_STREAM, IPPROTO_TCP },
        { SOCK_DGRAM, IPPROTO_UDP },
        { SOCK_RAW, 0 }
    };

    struct addrinfo *ai = NULL;

#ifdef HAVE_INET_PTON
    if (node && (!service || strspn(service, "0123456789") == strlen(service))) {
        int port = service ? (unsigned short)atoi(service): 0;
        int hint_family = hints ? hints->ai_family : PF_UNSPEC;
        int hint_socktype = hints ? hints->ai_socktype : 0;
        int hint_protocol = hints ? hints->ai_protocol : 0;
        char ipv4addr[4];
#ifdef AF_INET6
        char ipv6addr[16];
        if ((hint_family == PF_UNSPEC || hint_family == PF_INET6) &&
            strspn(node, "0123456789abcdefABCDEF.:") == strlen(node) &&
            inet_pton(AF_INET6, node, ipv6addr)) {
            int i;
            for (i = numberof(list)-1; 0 <= i; i--) {
                if ((hint_socktype == 0 || hint_socktype == list[i].socktype) &&
                    (hint_protocol == 0 || list[i].protocol == 0 || hint_protocol == list[i].protocol)) {
                    struct addrinfo *ai0 = xmalloc(sizeof(struct addrinfo));
                    struct sockaddr_in6 *sa = xmalloc(sizeof(struct sockaddr_in6));
                    MEMZERO(ai0, sizeof(struct addrinfo), 1);
                    INIT_SOCKADDR_IN6(sa, sizeof(struct sockaddr_in6));
                    memcpy(&sa->sin6_addr, ipv6addr, sizeof(ipv6addr));
                    sa->sin6_port = htons(port);
                    ai0->ai_family = PF_INET6;
                    ai0->ai_socktype = list[i].socktype;
                    ai0->ai_protocol = hint_protocol ? hint_protocol : list[i].protocol;
                    ai0->ai_addrlen = sizeof(struct sockaddr_in6);
                    ai0->ai_addr = (struct sockaddr *)sa;
                    ai0->ai_canonname = NULL;
                    ai0->ai_next = ai;
                    ai = ai0;
                }
            }
        }
        else
#endif
        if ((hint_family == PF_UNSPEC || hint_family == PF_INET) &&
            strspn(node, "0123456789.") == strlen(node) &&
            inet_pton(AF_INET, node, ipv4addr)) {
            int i;
            for (i = numberof(list)-1; 0 <= i; i--) {
                if ((hint_socktype == 0 || hint_socktype == list[i].socktype) &&
                    (hint_protocol == 0 || list[i].protocol == 0 || hint_protocol == list[i].protocol)) {
                    struct addrinfo *ai0 = xmalloc(sizeof(struct addrinfo));
                    struct sockaddr_in *sa = xmalloc(sizeof(struct sockaddr_in));
                    MEMZERO(ai0, sizeof(struct addrinfo), 1);
                    INIT_SOCKADDR_IN(sa, sizeof(struct sockaddr_in));
                    memcpy(&sa->sin_addr, ipv4addr, sizeof(ipv4addr));
                    sa->sin_port = htons(port);
                    ai0->ai_family = PF_INET;
                    ai0->ai_socktype = list[i].socktype;
                    ai0->ai_protocol = hint_protocol ? hint_protocol : list[i].protocol;
                    ai0->ai_addrlen = sizeof(struct sockaddr_in);
                    ai0->ai_addr = (struct sockaddr *)sa;
                    ai0->ai_canonname = NULL;
                    ai0->ai_next = ai;
                    ai = ai0;
                }
            }
        }
        if (ai) {
            *res = ai;
            return 0;
        }
    }
#endif
    return EAI_FAIL;
}

int
rb_getaddrinfo(const char *node, const char *service,
               const struct addrinfo *hints,
               struct rb_addrinfo **res)
{
    struct addrinfo *ai;
    int ret;
    int allocated_by_malloc = 0;

    ret = numeric_getaddrinfo(node, service, hints, &ai);
    if (ret == 0)
        allocated_by_malloc = 1;
    else {
#ifdef GETADDRINFO_EMU
        ret = getaddrinfo(node, service, hints, &ai);
#else
        struct getaddrinfo_arg arg;
        MEMZERO(&arg, sizeof arg, 1);
        arg.node = node;
        arg.service = service;
        arg.hints = hints;
        arg.res = &ai;
        ret = (int)(VALUE)rb_thread_call_without_gvl(nogvl_getaddrinfo, &arg, RUBY_UBF_IO, 0);
#endif
    }

    if (ret == 0) {
        *res = (struct rb_addrinfo *)xmalloc(sizeof(struct rb_addrinfo));
        (*res)->allocated_by_malloc = allocated_by_malloc;
        (*res)->ai = ai;
    }
    return ret;
}

void
rb_freeaddrinfo(struct rb_addrinfo *ai)
{
    if (!ai->allocated_by_malloc)
        freeaddrinfo(ai->ai);
    else {
        struct addrinfo *ai1, *ai2;
        ai1 = ai->ai;
        while (ai1) {
            ai2 = ai1->ai_next;
            xfree(ai1->ai_addr);
            xfree(ai1);
            ai1 = ai2;
        }
    }
    xfree(ai);
}

#ifndef GETADDRINFO_EMU
struct getnameinfo_arg
{
    const struct sockaddr *sa;
    socklen_t salen;
    char *host;
    size_t hostlen;
    char *serv;
    size_t servlen;
    int flags;
};

static void *
nogvl_getnameinfo(void *arg)
{
    struct getnameinfo_arg *ptr = arg;
    return (void *)(VALUE)getnameinfo(ptr->sa, ptr->salen,
				      ptr->host, (socklen_t)ptr->hostlen,
				      ptr->serv, (socklen_t)ptr->servlen,
				      ptr->flags);
}
#endif

int
rb_getnameinfo(const struct sockaddr *sa, socklen_t salen,
           char *host, size_t hostlen,
           char *serv, size_t servlen, int flags)
{
#ifdef GETADDRINFO_EMU
    return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
#else
    struct getnameinfo_arg arg;
    int ret;
    arg.sa = sa;
    arg.salen = salen;
    arg.host = host;
    arg.hostlen = hostlen;
    arg.serv = serv;
    arg.servlen = servlen;
    arg.flags = flags;
    ret = (int)(VALUE)rb_thread_call_without_gvl(nogvl_getnameinfo, &arg, RUBY_UBF_IO, 0);
    return ret;
#endif
}

static void
make_ipaddr0(struct sockaddr *addr, socklen_t addrlen, char *buf, size_t buflen)
{
    int error;

    error = rb_getnameinfo(addr, addrlen, buf, buflen, NULL, 0, NI_NUMERICHOST);
    if (error) {
        rsock_raise_socket_error("getnameinfo", error);
    }
}

VALUE
rsock_make_ipaddr(struct sockaddr *addr, socklen_t addrlen)
{
    char hbuf[1024];

    make_ipaddr0(addr, addrlen, hbuf, sizeof(hbuf));
    return rb_str_new2(hbuf);
}

static void
make_inetaddr(unsigned int host, char *buf, size_t buflen)
{
    struct sockaddr_in sin;

    INIT_SOCKADDR_IN(&sin, sizeof(sin));
    sin.sin_addr.s_addr = host;
    make_ipaddr0((struct sockaddr*)&sin, sizeof(sin), buf, buflen);
}

static int
str_is_number(const char *p)
{
    char *ep;

    if (!p || *p == '\0')
       return 0;
    ep = NULL;
    (void)STRTOUL(p, &ep, 10);
    if (ep && *ep == '\0')
       return 1;
    else
       return 0;
}

static char*
host_str(VALUE host, char *hbuf, size_t hbuflen, int *flags_ptr)
{
    if (NIL_P(host)) {
        return NULL;
    }
    else if (rb_obj_is_kind_of(host, rb_cInteger)) {
        unsigned int i = NUM2UINT(host);

        make_inetaddr(htonl(i), hbuf, hbuflen);
        if (flags_ptr) *flags_ptr |= AI_NUMERICHOST;
        return hbuf;
    }
    else {
        char *name;

        SafeStringValue(host);
        name = RSTRING_PTR(host);
        if (!name || *name == 0 || (name[0] == '<' && strcmp(name, "<any>") == 0)) {
            make_inetaddr(INADDR_ANY, hbuf, hbuflen);
            if (flags_ptr) *flags_ptr |= AI_NUMERICHOST;
        }
        else if (name[0] == '<' && strcmp(name, "<broadcast>") == 0) {
            make_inetaddr(INADDR_BROADCAST, hbuf, hbuflen);
            if (flags_ptr) *flags_ptr |= AI_NUMERICHOST;
        }
        else if (strlen(name) >= hbuflen) {
            rb_raise(rb_eArgError, "hostname too long (%"PRIuSIZE")",
                strlen(name));
        }
        else {
            strcpy(hbuf, name);
        }
        return hbuf;
    }
}

static char*
port_str(VALUE port, char *pbuf, size_t pbuflen, int *flags_ptr)
{
    if (NIL_P(port)) {
        return 0;
    }
    else if (FIXNUM_P(port)) {
        snprintf(pbuf, pbuflen, "%ld", FIX2LONG(port));
#ifdef AI_NUMERICSERV
        if (flags_ptr) *flags_ptr |= AI_NUMERICSERV;
#endif
        return pbuf;
    }
    else {
        char *serv;

        SafeStringValue(port);
        serv = RSTRING_PTR(port);
        if (strlen(serv) >= pbuflen) {
            rb_raise(rb_eArgError, "service name too long (%"PRIuSIZE")",
                strlen(serv));
        }
        strcpy(pbuf, serv);
        return pbuf;
    }
}

struct rb_addrinfo*
rsock_getaddrinfo(VALUE host, VALUE port, struct addrinfo *hints, int socktype_hack)
{
    struct rb_addrinfo* res = NULL;
    char *hostp, *portp;
    int error;
    char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
    int additional_flags = 0;

    hostp = host_str(host, hbuf, sizeof(hbuf), &additional_flags);
    portp = port_str(port, pbuf, sizeof(pbuf), &additional_flags);

    if (socktype_hack && hints->ai_socktype == 0 && str_is_number(portp)) {
       hints->ai_socktype = SOCK_DGRAM;
    }
    hints->ai_flags |= additional_flags;

    error = rb_getaddrinfo(hostp, portp, hints, &res);
    if (error) {
        if (hostp && hostp[strlen(hostp)-1] == '\n') {
            rb_raise(rb_eSocket, "newline at the end of hostname");
        }
        rsock_raise_socket_error("getaddrinfo", error);
    }

    return res;
}

struct rb_addrinfo*
rsock_addrinfo(VALUE host, VALUE port, int socktype, int flags)
{
    struct addrinfo hints;

    MEMZERO(&hints, struct addrinfo, 1);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = socktype;
    hints.ai_flags = flags;
    return rsock_getaddrinfo(host, port, &hints, 1);
}

VALUE
rsock_ipaddr(struct sockaddr *sockaddr, socklen_t sockaddrlen, int norevlookup)
{
    VALUE family, port, addr1, addr2;
    VALUE ary;
    int error;
    char hbuf[1024], pbuf[1024];
    ID id;

    id = rsock_intern_family(sockaddr->sa_family);
    if (id) {
        family = rb_str_dup(rb_id2str(id));
    }
    else {
        sprintf(pbuf, "unknown:%d", sockaddr->sa_family);
        family = rb_str_new2(pbuf);
    }

    addr1 = Qnil;
    if (!norevlookup) {
        error = rb_getnameinfo(sockaddr, sockaddrlen, hbuf, sizeof(hbuf),
                               NULL, 0, 0);
        if (! error) {
            addr1 = rb_str_new2(hbuf);
        }
    }
    error = rb_getnameinfo(sockaddr, sockaddrlen, hbuf, sizeof(hbuf),
                           pbuf, sizeof(pbuf), NI_NUMERICHOST | NI_NUMERICSERV);
    if (error) {
        rsock_raise_socket_error("getnameinfo", error);
    }
    addr2 = rb_str_new2(hbuf);
    if (addr1 == Qnil) {
        addr1 = addr2;
    }
    port = INT2FIX(atoi(pbuf));
    ary = rb_ary_new3(4, family, port, addr1, addr2);

    return ary;
}

#ifdef HAVE_SYS_UN_H
VALUE
rsock_unixpath_str(struct sockaddr_un *sockaddr, socklen_t len)
{
    char *s, *e;
    s = sockaddr->sun_path;
    e = (char *)sockaddr + len;
    while (s < e && *(e-1) == '\0')
        e--;
    if (s <= e)
        return rb_str_new(s, e-s);
    else
        return rb_str_new2("");
}

VALUE
rsock_unixaddr(struct sockaddr_un *sockaddr, socklen_t len)
{
    return rb_assoc_new(rb_str_new2("AF_UNIX"),
                        rsock_unixpath_str(sockaddr, len));
}

socklen_t
rsock_unix_sockaddr_len(VALUE path)
{
#ifdef __linux__
    if (RSTRING_LEN(path) == 0) {
	/* autobind; see unix(7) for details. */
	return (socklen_t) sizeof(sa_family_t);
    }
    else if (RSTRING_PTR(path)[0] == '\0') {
	/* abstract namespace; see unix(7) for details. */
        if (SOCKLEN_MAX - offsetof(struct sockaddr_un, sun_path) < (size_t)RSTRING_LEN(path))
            rb_raise(rb_eArgError, "Linux abstract socket too long");
	return (socklen_t) offsetof(struct sockaddr_un, sun_path) +
	    RSTRING_SOCKLEN(path);
    }
    else {
#endif
	return (socklen_t) sizeof(struct sockaddr_un);
#ifdef __linux__
    }
#endif
}
#endif

struct hostent_arg {
    VALUE host;
    struct rb_addrinfo* addr;
    VALUE (*ipaddr)(struct sockaddr*, socklen_t);
};

static VALUE
make_hostent_internal(struct hostent_arg *arg)
{
    VALUE host = arg->host;
    struct addrinfo* addr = arg->addr->ai;
    VALUE (*ipaddr)(struct sockaddr*, socklen_t) = arg->ipaddr;

    struct addrinfo *ai;
    struct hostent *h;
    VALUE ary, names;
    char **pch;
    const char* hostp;
    char hbuf[NI_MAXHOST];

    ary = rb_ary_new();
    if (addr->ai_canonname) {
        hostp = addr->ai_canonname;
    }
    else {
        hostp = host_str(host, hbuf, sizeof(hbuf), NULL);
    }
    rb_ary_push(ary, rb_str_new2(hostp));

    if (addr->ai_canonname && (h = gethostbyname(addr->ai_canonname))) {
        names = rb_ary_new();
        if (h->h_aliases != NULL) {
            for (pch = h->h_aliases; *pch; pch++) {
                rb_ary_push(names, rb_str_new2(*pch));
            }
        }
    }
    else {
        names = rb_ary_new2(0);
    }
    rb_ary_push(ary, names);
    rb_ary_push(ary, INT2NUM(addr->ai_family));
    for (ai = addr; ai; ai = ai->ai_next) {
        rb_ary_push(ary, (*ipaddr)(ai->ai_addr, ai->ai_addrlen));
    }

    return ary;
}

VALUE
rsock_freeaddrinfo(VALUE arg)
{
    struct rb_addrinfo *addr = (struct rb_addrinfo *)arg;
    rb_freeaddrinfo(addr);
    return Qnil;
}

VALUE
rsock_make_hostent(VALUE host, struct rb_addrinfo *addr, VALUE (*ipaddr)(struct sockaddr *, socklen_t))
{
    struct hostent_arg arg;

    arg.host = host;
    arg.addr = addr;
    arg.ipaddr = ipaddr;
    return rb_ensure(make_hostent_internal, (VALUE)&arg,
                     rsock_freeaddrinfo, (VALUE)addr);
}

typedef struct {
    VALUE inspectname;
    VALUE canonname;
    int pfamily;
    int socktype;
    int protocol;
    socklen_t sockaddr_len;
    union_sockaddr addr;
} rb_addrinfo_t;

static void
addrinfo_mark(void *ptr)
{
    rb_addrinfo_t *rai = ptr;
    if (rai) {
        rb_gc_mark(rai->inspectname);
        rb_gc_mark(rai->canonname);
    }
}

#define addrinfo_free RUBY_TYPED_DEFAULT_FREE

static size_t
addrinfo_memsize(const void *ptr)
{
    return ptr ? sizeof(rb_addrinfo_t) : 0;
}

static const rb_data_type_t addrinfo_type = {
    "socket/addrinfo",
    {addrinfo_mark, addrinfo_free, addrinfo_memsize,},
};

static VALUE
addrinfo_s_allocate(VALUE klass)
{
    return TypedData_Wrap_Struct(klass, &addrinfo_type, 0);
}

#define IS_ADDRINFO(obj) rb_typeddata_is_kind_of((obj), &addrinfo_type)
static inline rb_addrinfo_t *
check_addrinfo(VALUE self)
{
    return rb_check_typeddata(self, &addrinfo_type);
}

static rb_addrinfo_t *
get_addrinfo(VALUE self)
{
    rb_addrinfo_t *rai = check_addrinfo(self);

    if (!rai) {
        rb_raise(rb_eTypeError, "uninitialized socket address");
    }
    return rai;
}


static rb_addrinfo_t *
alloc_addrinfo()
{
    rb_addrinfo_t *rai = ALLOC(rb_addrinfo_t);
    memset(rai, 0, sizeof(rb_addrinfo_t));
    rai->inspectname = Qnil;
    rai->canonname = Qnil;
    return rai;
}

static void
init_addrinfo(rb_addrinfo_t *rai, struct sockaddr *sa, socklen_t len,
              int pfamily, int socktype, int protocol,
              VALUE canonname, VALUE inspectname)
{
    if ((socklen_t)sizeof(rai->addr) < len)
        rb_raise(rb_eArgError, "sockaddr string too big");
    memcpy((void *)&rai->addr, (void *)sa, len);
    rai->sockaddr_len = len;

    rai->pfamily = pfamily;
    rai->socktype = socktype;
    rai->protocol = protocol;
    rai->canonname = canonname;
    rai->inspectname = inspectname;
}

VALUE
rsock_addrinfo_new(struct sockaddr *addr, socklen_t len,
                   int family, int socktype, int protocol,
                   VALUE canonname, VALUE inspectname)
{
    VALUE a;
    rb_addrinfo_t *rai;

    a = addrinfo_s_allocate(rb_cAddrinfo);
    DATA_PTR(a) = rai = alloc_addrinfo();
    init_addrinfo(rai, addr, len, family, socktype, protocol, canonname, inspectname);
    return a;
}

static struct rb_addrinfo *
call_getaddrinfo(VALUE node, VALUE service,
                 VALUE family, VALUE socktype, VALUE protocol, VALUE flags,
                 int socktype_hack)
{
    struct addrinfo hints;
    struct rb_addrinfo *res;

    MEMZERO(&hints, struct addrinfo, 1);
    hints.ai_family = NIL_P(family) ? PF_UNSPEC : rsock_family_arg(family);

    if (!NIL_P(socktype)) {
	hints.ai_socktype = rsock_socktype_arg(socktype);
    }
    if (!NIL_P(protocol)) {
	hints.ai_protocol = NUM2INT(protocol);
    }
    if (!NIL_P(flags)) {
	hints.ai_flags = NUM2INT(flags);
    }
    res = rsock_getaddrinfo(node, service, &hints, socktype_hack);

    if (res == NULL)
	rb_raise(rb_eSocket, "host not found");
    return res;
}

static VALUE make_inspectname(VALUE node, VALUE service, struct addrinfo *res);

static void
init_addrinfo_getaddrinfo(rb_addrinfo_t *rai, VALUE node, VALUE service,
                          VALUE family, VALUE socktype, VALUE protocol, VALUE flags,
                          VALUE inspectnode, VALUE inspectservice)
{
    struct rb_addrinfo *res = call_getaddrinfo(node, service, family, socktype, protocol, flags, 1);
    VALUE canonname;
    VALUE inspectname = rb_str_equal(node, inspectnode) ? Qnil : make_inspectname(inspectnode, inspectservice, res->ai);

    canonname = Qnil;
    if (res->ai->ai_canonname) {
        canonname = rb_tainted_str_new_cstr(res->ai->ai_canonname);
        OBJ_FREEZE(canonname);
    }

    init_addrinfo(rai, res->ai->ai_addr, res->ai->ai_addrlen,
                  NUM2INT(family), NUM2INT(socktype), NUM2INT(protocol),
                  canonname, inspectname);

    rb_freeaddrinfo(res);
}

static VALUE
make_inspectname(VALUE node, VALUE service, struct addrinfo *res)
{
    VALUE inspectname = Qnil;

    if (res) {
        /* drop redundant information which also shown in address:port part. */
        char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
        int ret;
        ret = rb_getnameinfo(res->ai_addr, res->ai_addrlen, hbuf,
                             sizeof(hbuf), pbuf, sizeof(pbuf),
                             NI_NUMERICHOST|NI_NUMERICSERV);
        if (ret == 0) {
            if (RB_TYPE_P(node, T_STRING) && strcmp(hbuf, RSTRING_PTR(node)) == 0)
                node = Qnil;
            if (RB_TYPE_P(service, T_STRING) && strcmp(pbuf, RSTRING_PTR(service)) == 0)
                service = Qnil;
            else if (RB_TYPE_P(service, T_FIXNUM) && atoi(pbuf) == FIX2INT(service))
                service = Qnil;
        }
    }

    if (RB_TYPE_P(node, T_STRING)) {
        inspectname = rb_str_dup(node);
    }
    if (RB_TYPE_P(service, T_STRING)) {
        if (NIL_P(inspectname))
            inspectname = rb_sprintf(":%s", StringValueCStr(service));
        else
            rb_str_catf(inspectname, ":%s", StringValueCStr(service));
    }
    else if (RB_TYPE_P(service, T_FIXNUM) && FIX2INT(service) != 0)
    {
        if (NIL_P(inspectname))
            inspectname = rb_sprintf(":%d", FIX2INT(service));
        else
            rb_str_catf(inspectname, ":%d", FIX2INT(service));
    }
    if (!NIL_P(inspectname)) {
        OBJ_INFECT(inspectname, node);
        OBJ_INFECT(inspectname, service);
        OBJ_FREEZE(inspectname);
    }
    return inspectname;
}

static VALUE
addrinfo_firstonly_new(VALUE node, VALUE service, VALUE family, VALUE socktype, VALUE protocol, VALUE flags)
{
    VALUE ret;
    VALUE canonname;
    VALUE inspectname;

    struct rb_addrinfo *res = call_getaddrinfo(node, service, family, socktype, protocol, flags, 0);

    inspectname = make_inspectname(node, service, res->ai);

    canonname = Qnil;
    if (res->ai->ai_canonname) {
        canonname = rb_tainted_str_new_cstr(res->ai->ai_canonname);
        OBJ_FREEZE(canonname);
    }

    ret = rsock_addrinfo_new(res->ai->ai_addr, res->ai->ai_addrlen,
                             res->ai->ai_family, res->ai->ai_socktype,
                             res->ai->ai_protocol,
                             canonname, inspectname);

    rb_freeaddrinfo(res);
    return ret;
}

static VALUE
addrinfo_list_new(VALUE node, VALUE service, VALUE family, VALUE socktype, VALUE protocol, VALUE flags)
{
    VALUE ret;
    struct addrinfo *r;
    VALUE inspectname;

    struct rb_addrinfo *res = call_getaddrinfo(node, service, family, socktype, protocol, flags, 0);

    inspectname = make_inspectname(node, service, res->ai);

    ret = rb_ary_new();
    for (r = res->ai; r; r = r->ai_next) {
        VALUE addr;
        VALUE canonname = Qnil;

        if (r->ai_canonname) {
            canonname = rb_tainted_str_new_cstr(r->ai_canonname);
            OBJ_FREEZE(canonname);
        }

        addr = rsock_addrinfo_new(r->ai_addr, r->ai_addrlen,
                                  r->ai_family, r->ai_socktype, r->ai_protocol,
                                  canonname, inspectname);

        rb_ary_push(ret, addr);
    }

    rb_freeaddrinfo(res);
    return ret;
}


#ifdef HAVE_SYS_UN_H
static void
init_unix_addrinfo(rb_addrinfo_t *rai, VALUE path, int socktype)
{
    struct sockaddr_un un;
    socklen_t len;

    StringValue(path);

    if (sizeof(un.sun_path) < (size_t)RSTRING_LEN(path))
        rb_raise(rb_eArgError,
            "too long unix socket path (%"PRIuSIZE" bytes given but %"PRIuSIZE" bytes max)",
            (size_t)RSTRING_LEN(path), sizeof(un.sun_path));

    INIT_SOCKADDR_UN(&un, sizeof(struct sockaddr_un));
    memcpy((void*)&un.sun_path, RSTRING_PTR(path), RSTRING_LEN(path));

    len = rsock_unix_sockaddr_len(path);
    init_addrinfo(rai, (struct sockaddr *)&un, len,
		  PF_UNIX, socktype, 0, Qnil, Qnil);
}
#endif

/*
 * call-seq:
 *   Addrinfo.new(sockaddr)                             => addrinfo
 *   Addrinfo.new(sockaddr, family)                     => addrinfo
 *   Addrinfo.new(sockaddr, family, socktype)           => addrinfo
 *   Addrinfo.new(sockaddr, family, socktype, protocol) => addrinfo
 *
 * returns a new instance of Addrinfo.
 * The instance contains sockaddr, family, socktype, protocol.
 * sockaddr means struct sockaddr which can be used for connect(2), etc.
 * family, socktype and protocol are integers which is used for arguments of socket(2).
 *
 * sockaddr is specified as an array or a string.
 * The array should be compatible to the value of IPSocket#addr or UNIXSocket#addr.
 * The string should be struct sockaddr as generated by
 * Socket.sockaddr_in or Socket.unpack_sockaddr_un.
 *
 * sockaddr examples:
 * - ["AF_INET", 46102, "localhost.localdomain", "127.0.0.1"]
 * - ["AF_INET6", 42304, "ip6-localhost", "::1"]
 * - ["AF_UNIX", "/tmp/sock"]
 * - Socket.sockaddr_in("smtp", "2001:DB8::1")
 * - Socket.sockaddr_in(80, "172.18.22.42")
 * - Socket.sockaddr_in(80, "www.ruby-lang.org")
 * - Socket.sockaddr_un("/tmp/sock")
 *
 * In an AF_INET/AF_INET6 sockaddr array, the 4th element,
 * numeric IP address, is used to construct socket address in the Addrinfo instance.
 * If the 3rd element, textual host name, is non-nil, it is also recorded but used only for Addrinfo#inspect.
 *
 * family is specified as an integer to specify the protocol family such as Socket::PF_INET.
 * It can be a symbol or a string which is the constant name
 * with or without PF_ prefix such as :INET, :INET6, :UNIX, "PF_INET", etc.
 * If omitted, PF_UNSPEC is assumed.
 *
 * socktype is specified as an integer to specify the socket type such as Socket::SOCK_STREAM.
 * It can be a symbol or a string which is the constant name
 * with or without SOCK_ prefix such as :STREAM, :DGRAM, :RAW, "SOCK_STREAM", etc.
 * If omitted, 0 is assumed.
 *
 * protocol is specified as an integer to specify the protocol such as Socket::IPPROTO_TCP.
 * It must be an integer, unlike family and socktype.
 * If omitted, 0 is assumed.
 * Note that 0 is reasonable value for most protocols, except raw socket.
 *
 */
static VALUE
addrinfo_initialize(int argc, VALUE *argv, VALUE self)
{
    rb_addrinfo_t *rai;
    VALUE sockaddr_arg, sockaddr_ary, pfamily, socktype, protocol;
    int i_pfamily, i_socktype, i_protocol;
    struct sockaddr *sockaddr_ptr;
    socklen_t sockaddr_len;
    VALUE canonname = Qnil, inspectname = Qnil;

    if (check_addrinfo(self))
        rb_raise(rb_eTypeError, "already initialized socket address");
    DATA_PTR(self) = rai = alloc_addrinfo();

    rb_scan_args(argc, argv, "13", &sockaddr_arg, &pfamily, &socktype, &protocol);

    i_pfamily = NIL_P(pfamily) ? PF_UNSPEC : rsock_family_arg(pfamily);
    i_socktype = NIL_P(socktype) ? 0 : rsock_socktype_arg(socktype);
    i_protocol = NIL_P(protocol) ? 0 : NUM2INT(protocol);

    sockaddr_ary = rb_check_array_type(sockaddr_arg);
    if (!NIL_P(sockaddr_ary)) {
        VALUE afamily = rb_ary_entry(sockaddr_ary, 0);
        int af;
        StringValue(afamily);
        if (rsock_family_to_int(RSTRING_PTR(afamily), RSTRING_LEN(afamily), &af) == -1)
	    rb_raise(rb_eSocket, "unknown address family: %s", StringValueCStr(afamily));
        switch (af) {
          case AF_INET: /* ["AF_INET", 46102, "localhost.localdomain", "127.0.0.1"] */
#ifdef INET6
          case AF_INET6: /* ["AF_INET6", 42304, "ip6-localhost", "::1"] */
#endif
          {
            VALUE service = rb_ary_entry(sockaddr_ary, 1);
            VALUE nodename = rb_ary_entry(sockaddr_ary, 2);
            VALUE numericnode = rb_ary_entry(sockaddr_ary, 3);
            int flags;

            service = INT2NUM(NUM2INT(service));
            if (!NIL_P(nodename))
                StringValue(nodename);
            StringValue(numericnode);
            flags = AI_NUMERICHOST;
#ifdef AI_NUMERICSERV
            flags |= AI_NUMERICSERV;
#endif

            init_addrinfo_getaddrinfo(rai, numericnode, service,
                    INT2NUM(i_pfamily ? i_pfamily : af), INT2NUM(i_socktype), INT2NUM(i_protocol),
                    INT2NUM(flags),
                    nodename, service);
            break;
          }

#ifdef HAVE_SYS_UN_H
          case AF_UNIX: /* ["AF_UNIX", "/tmp/sock"] */
          {
            VALUE path = rb_ary_entry(sockaddr_ary, 1);
            StringValue(path);
            init_unix_addrinfo(rai, path, SOCK_STREAM);
            break;
          }
#endif

          default:
            rb_raise(rb_eSocket, "unexpected address family");
        }
    }
    else {
        StringValue(sockaddr_arg);
        sockaddr_ptr = (struct sockaddr *)RSTRING_PTR(sockaddr_arg);
        sockaddr_len = RSTRING_SOCKLEN(sockaddr_arg);
        init_addrinfo(rai, sockaddr_ptr, sockaddr_len,
                      i_pfamily, i_socktype, i_protocol,
                      canonname, inspectname);
    }

    return self;
}

static int
get_afamily(struct sockaddr *addr, socklen_t len)
{
    if ((socklen_t)((char*)&addr->sa_family + sizeof(addr->sa_family) - (char*)addr) <= len)
        return addr->sa_family;
    else
        return AF_UNSPEC;
}

static int
ai_get_afamily(rb_addrinfo_t *rai)
{
    return get_afamily(&rai->addr.addr, rai->sockaddr_len);
}

static VALUE
inspect_sockaddr(VALUE addrinfo, VALUE ret)
{
    rb_addrinfo_t *rai = get_addrinfo(addrinfo);
    union_sockaddr *sockaddr = &rai->addr;
    socklen_t socklen = rai->sockaddr_len;
    return rsock_inspect_sockaddr((struct sockaddr *)sockaddr, socklen, ret);
}

VALUE
rsock_inspect_sockaddr(struct sockaddr *sockaddr_arg, socklen_t socklen, VALUE ret)
{
    union_sockaddr *sockaddr = (union_sockaddr *)sockaddr_arg;
    if (socklen == 0) {
        rb_str_cat2(ret, "empty-sockaddr");
    }
    else if ((long)socklen < ((char*)&sockaddr->addr.sa_family + sizeof(sockaddr->addr.sa_family)) - (char*)sockaddr)
        rb_str_cat2(ret, "too-short-sockaddr");
    else {
        switch (sockaddr->addr.sa_family) {
          case AF_UNSPEC:
	  {
	    rb_str_cat2(ret, "UNSPEC");
            break;
	  }

          case AF_INET:
          {
            struct sockaddr_in *addr;
            int port;
	    addr = &sockaddr->in;
	    if ((socklen_t)(((char*)&addr->sin_addr)-(char*)addr+0+1) <= socklen)
		rb_str_catf(ret, "%d", ((unsigned char*)&addr->sin_addr)[0]);
	    else
		rb_str_cat2(ret, "?");
	    if ((socklen_t)(((char*)&addr->sin_addr)-(char*)addr+1+1) <= socklen)
		rb_str_catf(ret, ".%d", ((unsigned char*)&addr->sin_addr)[1]);
	    else
		rb_str_cat2(ret, ".?");
	    if ((socklen_t)(((char*)&addr->sin_addr)-(char*)addr+2+1) <= socklen)
		rb_str_catf(ret, ".%d", ((unsigned char*)&addr->sin_addr)[2]);
	    else
		rb_str_cat2(ret, ".?");
	    if ((socklen_t)(((char*)&addr->sin_addr)-(char*)addr+3+1) <= socklen)
		rb_str_catf(ret, ".%d", ((unsigned char*)&addr->sin_addr)[3]);
	    else
		rb_str_cat2(ret, ".?");

	    if ((socklen_t)(((char*)&addr->sin_port)-(char*)addr+(int)sizeof(addr->sin_port)) < socklen) {
		port = ntohs(addr->sin_port);
		if (port)
		    rb_str_catf(ret, ":%d", port);
	    }
	    else {
		rb_str_cat2(ret, ":?");
	    }
	    if ((socklen_t)sizeof(struct sockaddr_in) != socklen)
		rb_str_catf(ret, " (%d bytes for %d bytes sockaddr_in)",
		  (int)socklen,
		  (int)sizeof(struct sockaddr_in));
            break;
          }

#ifdef AF_INET6
          case AF_INET6:
          {
            struct sockaddr_in6 *addr;
            char hbuf[1024];
            int port;
            int error;
            if (socklen < (socklen_t)sizeof(struct sockaddr_in6)) {
                rb_str_catf(ret, "too-short-AF_INET6-sockaddr %d bytes", (int)socklen);
            }
            else {
                addr = &sockaddr->in6;
                /* use getnameinfo for scope_id.
                 * RFC 4007: IPv6 Scoped Address Architecture
                 * draft-ietf-ipv6-scope-api-00.txt: Scoped Address Extensions to the IPv6 Basic Socket API
                 */
                error = getnameinfo(&sockaddr->addr, socklen,
                                    hbuf, (socklen_t)sizeof(hbuf), NULL, 0,
                                    NI_NUMERICHOST|NI_NUMERICSERV);
                if (error) {
                    rsock_raise_socket_error("getnameinfo", error);
                }
                if (addr->sin6_port == 0) {
                    rb_str_cat2(ret, hbuf);
                }
                else {
                    port = ntohs(addr->sin6_port);
                    rb_str_catf(ret, "[%s]:%d", hbuf, port);
                }
                if ((socklen_t)sizeof(struct sockaddr_in6) < socklen)
                    rb_str_catf(ret, "(sockaddr %d bytes too long)", (int)(socklen - sizeof(struct sockaddr_in6)));
            }
            break;
          }
#endif

#ifdef HAVE_SYS_UN_H
          case AF_UNIX:
          {
            struct sockaddr_un *addr = &sockaddr->un;
            char *p, *s, *e;
            s = addr->sun_path;
            e = (char*)addr + socklen;
            while (s < e && *(e-1) == '\0')
                e--;
            if (e < s)
                rb_str_cat2(ret, "too-short-AF_UNIX-sockaddr");
            else if (s == e)
                rb_str_cat2(ret, "empty-path-AF_UNIX-sockaddr");
            else {
                int printable_only = 1;
                p = s;
                while (p < e) {
                    printable_only = printable_only && ISPRINT(*p) && !ISSPACE(*p);
                    p++;
                }
                if (printable_only) { /* only printable, no space */
                    if (s[0] != '/') /* relative path */
                        rb_str_cat2(ret, "UNIX ");
                    rb_str_cat(ret, s, p - s);
                }
                else {
                    rb_str_cat2(ret, "UNIX");
                    while (s < e)
                        rb_str_catf(ret, ":%02x", (unsigned char)*s++);
                }
            }
            break;
          }
#endif

#ifdef AF_PACKET
          /* GNU/Linux */
          case AF_PACKET:
          {
            struct sockaddr_ll *addr;
            const char *sep = "[";
#define CATSEP do { rb_str_cat2(ret, sep); sep = " "; } while (0);

            addr = (struct sockaddr_ll *)sockaddr;

            rb_str_cat2(ret, "PACKET");

            if (offsetof(struct sockaddr_ll, sll_protocol) + sizeof(addr->sll_protocol) <= (size_t)socklen) {
                CATSEP;
                rb_str_catf(ret, "protocol=%d", ntohs(addr->sll_protocol));
            }
            if (offsetof(struct sockaddr_ll, sll_ifindex) + sizeof(addr->sll_ifindex) <= (size_t)socklen) {
                char buf[IFNAMSIZ];
                CATSEP;
                if (if_indextoname(addr->sll_ifindex, buf) == NULL)
                    rb_str_catf(ret, "ifindex=%d", addr->sll_ifindex);
                else
                    rb_str_catf(ret, "%s", buf);
            }
            if (offsetof(struct sockaddr_ll, sll_hatype) + sizeof(addr->sll_hatype) <= (size_t)socklen) {
                CATSEP;
                rb_str_catf(ret, "hatype=%d", addr->sll_hatype);
            }
            if (offsetof(struct sockaddr_ll, sll_pkttype) + sizeof(addr->sll_pkttype) <= (size_t)socklen) {
                CATSEP;
                if (addr->sll_pkttype == PACKET_HOST)
                    rb_str_cat2(ret, "HOST");
                else if (addr->sll_pkttype == PACKET_BROADCAST)
                    rb_str_cat2(ret, "BROADCAST");
                else if (addr->sll_pkttype == PACKET_MULTICAST)
                    rb_str_cat2(ret, "MULTICAST");
                else if (addr->sll_pkttype == PACKET_OTHERHOST)
                    rb_str_cat2(ret, "OTHERHOST");
                else if (addr->sll_pkttype == PACKET_OUTGOING)
                    rb_str_cat2(ret, "OUTGOING");
                else
                    rb_str_catf(ret, "pkttype=%d", addr->sll_pkttype);
            }
            if (socklen != (socklen_t)(offsetof(struct sockaddr_ll, sll_addr) + addr->sll_halen)) {
                CATSEP;
                if (offsetof(struct sockaddr_ll, sll_halen) + sizeof(addr->sll_halen) <= (size_t)socklen) {
                    rb_str_catf(ret, "halen=%d", addr->sll_halen);
                }
            }
            if (offsetof(struct sockaddr_ll, sll_addr) < (size_t)socklen) {
                socklen_t len, i;
                CATSEP;
                rb_str_cat2(ret, "hwaddr");
                len = addr->sll_halen;
                if ((size_t)socklen < offsetof(struct sockaddr_ll, sll_addr) + len)
                    len = socklen - offsetof(struct sockaddr_ll, sll_addr);
                for (i = 0; i < len; i++) {
                    rb_str_cat2(ret, i == 0 ? "=" : ":");
                    rb_str_catf(ret, "%02x", addr->sll_addr[i]);
                }
            }

            if (socklen < (socklen_t)(offsetof(struct sockaddr_ll, sll_halen) + sizeof(addr->sll_halen)) ||
                (socklen_t)(offsetof(struct sockaddr_ll, sll_addr) + addr->sll_halen) != socklen) {
                CATSEP;
                rb_str_catf(ret, "(%d bytes for %d bytes sockaddr_ll)",
                    (int)socklen, (int)sizeof(struct sockaddr_ll));
            }

            rb_str_cat2(ret, "]");
#undef CATSEP

            break;
          }
#endif

#if defined(AF_LINK) && defined(HAVE_TYPE_STRUCT_SOCKADDR_DL)
	  /* AF_LINK is defined in 4.4BSD derivations since Net2.
	     link_ntoa is also defined at Net2.
             However Debian GNU/kFreeBSD defines AF_LINK but
             don't have link_ntoa.  */
          case AF_LINK:
	  {
	    /*
	     * Simple implementation using link_ntoa():
	     * This doesn't work on Debian GNU/kFreeBSD 6.0.7 (squeeze).
             * Also, the format is bit different.
	     *
	     * rb_str_catf(ret, "LINK %s", link_ntoa(&sockaddr->dl));
	     * break;
	     */
            struct sockaddr_dl *addr = &sockaddr->dl;
            char *np = NULL, *ap = NULL, *endp;
            int nlen = 0, alen = 0;
            int i, off;
            const char *sep = "[";
#define CATSEP do { rb_str_cat2(ret, sep); sep = " "; } while (0);

            rb_str_cat2(ret, "LINK");

            endp = ((char *)addr) + socklen;

            if (offsetof(struct sockaddr_dl, sdl_data) < socklen) {
                np = addr->sdl_data;
                nlen = addr->sdl_nlen;
                if (endp - np < nlen)
                    nlen = (int)(endp - np);
            }
            off = addr->sdl_nlen;

            if (offsetof(struct sockaddr_dl, sdl_data) + off < socklen) {
                ap = addr->sdl_data + off;
                alen = addr->sdl_alen;
                if (endp - ap < alen)
                    alen = (int)(endp - ap);
            }

	    CATSEP;
            if (np)
                rb_str_catf(ret, "%.*s", nlen, np);
            else
                rb_str_cat2(ret, "?");

            if (ap && 0 < alen) {
		CATSEP;
                for (i = 0; i < alen; i++)
                    rb_str_catf(ret, "%s%02x", i == 0 ? "" : ":", (unsigned char)ap[i]);
            }

            if (socklen < (socklen_t)(offsetof(struct sockaddr_dl, sdl_nlen) + sizeof(addr->sdl_nlen)) ||
                socklen < (socklen_t)(offsetof(struct sockaddr_dl, sdl_alen) + sizeof(addr->sdl_alen)) ||
                socklen < (socklen_t)(offsetof(struct sockaddr_dl, sdl_slen) + sizeof(addr->sdl_slen)) ||
                /* longer length is possible behavior because struct sockaddr_dl has "minimum work area, can be larger" as the last field.
                 * cf. Net2:/usr/src/sys/net/if_dl.h. */
                socklen < (socklen_t)(offsetof(struct sockaddr_dl, sdl_data) + addr->sdl_nlen + addr->sdl_alen + addr->sdl_slen)) {
		CATSEP;
                rb_str_catf(ret, "(%d bytes for %d bytes sockaddr_dl)",
                    (int)socklen, (int)sizeof(struct sockaddr_dl));
	    }

            rb_str_cat2(ret, "]");
#undef CATSEP
            break;
          }
#endif

          default:
          {
            ID id = rsock_intern_family(sockaddr->addr.sa_family);
            if (id == 0)
                rb_str_catf(ret, "unknown address family %d", sockaddr->addr.sa_family);
            else
                rb_str_catf(ret, "%s address format unknown", rb_id2name(id));
            break;
          }
        }
    }

    return ret;
}

/*
 * call-seq:
 *   addrinfo.inspect => string
 *
 * returns a string which shows addrinfo in human-readable form.
 *
 *   Addrinfo.tcp("localhost", 80).inspect #=> "#<Addrinfo: 127.0.0.1:80 TCP (localhost)>"
 *   Addrinfo.unix("/tmp/sock").inspect    #=> "#<Addrinfo: /tmp/sock SOCK_STREAM>"
 *
 */
static VALUE
addrinfo_inspect(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int internet_p;
    VALUE ret;

    ret = rb_sprintf("#<%s: ", rb_obj_classname(self));

    inspect_sockaddr(self, ret);

    if (rai->pfamily && ai_get_afamily(rai) != rai->pfamily) {
        ID id = rsock_intern_protocol_family(rai->pfamily);
        if (id)
            rb_str_catf(ret, " %s", rb_id2name(id));
        else
            rb_str_catf(ret, " PF_\?\?\?(%d)", rai->pfamily);
    }

    internet_p = rai->pfamily == PF_INET;
#ifdef INET6
    internet_p = internet_p || rai->pfamily == PF_INET6;
#endif
    if (internet_p && rai->socktype == SOCK_STREAM &&
        (rai->protocol == 0 || rai->protocol == IPPROTO_TCP)) {
        rb_str_cat2(ret, " TCP");
    }
    else if (internet_p && rai->socktype == SOCK_DGRAM &&
        (rai->protocol == 0 || rai->protocol == IPPROTO_UDP)) {
        rb_str_cat2(ret, " UDP");
    }
    else {
        if (rai->socktype) {
            ID id = rsock_intern_socktype(rai->socktype);
            if (id)
                rb_str_catf(ret, " %s", rb_id2name(id));
            else
                rb_str_catf(ret, " SOCK_\?\?\?(%d)", rai->socktype);
        }

        if (rai->protocol) {
            if (internet_p) {
                ID id = rsock_intern_ipproto(rai->protocol);
                if (id)
                    rb_str_catf(ret, " %s", rb_id2name(id));
                else
                    goto unknown_protocol;
            }
            else {
              unknown_protocol:
                rb_str_catf(ret, " UNKNOWN_PROTOCOL(%d)", rai->protocol);
            }
        }
    }

    if (!NIL_P(rai->canonname)) {
        VALUE name = rai->canonname;
        rb_str_catf(ret, " %s", StringValueCStr(name));
    }

    if (!NIL_P(rai->inspectname)) {
        VALUE name = rai->inspectname;
        rb_str_catf(ret, " (%s)", StringValueCStr(name));
    }

    rb_str_buf_cat2(ret, ">");
    return ret;
}

/*
 * call-seq:
 *   addrinfo.inspect_sockaddr => string
 *
 * returns a string which shows the sockaddr in _addrinfo_ with human-readable form.
 *
 *   Addrinfo.tcp("localhost", 80).inspect_sockaddr     #=> "127.0.0.1:80"
 *   Addrinfo.tcp("ip6-localhost", 80).inspect_sockaddr #=> "[::1]:80"
 *   Addrinfo.unix("/tmp/sock").inspect_sockaddr        #=> "/tmp/sock"
 *
 */
VALUE
rsock_addrinfo_inspect_sockaddr(VALUE self)
{
    return inspect_sockaddr(self, rb_str_new("", 0));
}

/* :nodoc: */
static VALUE
addrinfo_mdump(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    VALUE sockaddr, afamily, pfamily, socktype, protocol, canonname, inspectname;
    int afamily_int = ai_get_afamily(rai);
    ID id;

    id = rsock_intern_protocol_family(rai->pfamily);
    if (id == 0)
        rb_raise(rb_eSocket, "unknown protocol family: %d", rai->pfamily);
    pfamily = rb_id2str(id);

    if (rai->socktype == 0)
        socktype = INT2FIX(0);
    else {
        id = rsock_intern_socktype(rai->socktype);
        if (id == 0)
            rb_raise(rb_eSocket, "unknown socktype: %d", rai->socktype);
        socktype = rb_id2str(id);
    }

    if (rai->protocol == 0)
        protocol = INT2FIX(0);
    else if (IS_IP_FAMILY(afamily_int)) {
        id = rsock_intern_ipproto(rai->protocol);
        if (id == 0)
            rb_raise(rb_eSocket, "unknown IP protocol: %d", rai->protocol);
        protocol = rb_id2str(id);
    }
    else {
        rb_raise(rb_eSocket, "unknown protocol: %d", rai->protocol);
    }

    canonname = rai->canonname;

    inspectname = rai->inspectname;

    id = rsock_intern_family(afamily_int);
    if (id == 0)
        rb_raise(rb_eSocket, "unknown address family: %d", afamily_int);
    afamily = rb_id2str(id);

    switch(afamily_int) {
#ifdef HAVE_SYS_UN_H
      case AF_UNIX:
      {
        struct sockaddr_un *su = &rai->addr.un;
        char *s, *e;
        s = su->sun_path;
        e = (char*)su + rai->sockaddr_len;
        while (s < e && *(e-1) == '\0')
            e--;
        sockaddr = rb_str_new(s, e-s);
        break;
      }
#endif

      default:
      {
        char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
        int error;
        error = getnameinfo(&rai->addr.addr, rai->sockaddr_len,
                            hbuf, (socklen_t)sizeof(hbuf), pbuf, (socklen_t)sizeof(pbuf),
                            NI_NUMERICHOST|NI_NUMERICSERV);
        if (error) {
            rsock_raise_socket_error("getnameinfo", error);
        }
        sockaddr = rb_assoc_new(rb_str_new_cstr(hbuf), rb_str_new_cstr(pbuf));
        break;
      }
    }

    return rb_ary_new3(7, afamily, sockaddr, pfamily, socktype, protocol, canonname, inspectname);
}

/* :nodoc: */
static VALUE
addrinfo_mload(VALUE self, VALUE ary)
{
    VALUE v;
    VALUE canonname, inspectname;
    int afamily, pfamily, socktype, protocol;
    union_sockaddr ss;
    socklen_t len;
    rb_addrinfo_t *rai;

    if (check_addrinfo(self))
        rb_raise(rb_eTypeError, "already initialized socket address");

    ary = rb_convert_type(ary, T_ARRAY, "Array", "to_ary");

    v = rb_ary_entry(ary, 0);
    StringValue(v);
    if (rsock_family_to_int(RSTRING_PTR(v), RSTRING_LEN(v), &afamily) == -1)
        rb_raise(rb_eTypeError, "unexpected address family");

    v = rb_ary_entry(ary, 2);
    StringValue(v);
    if (rsock_family_to_int(RSTRING_PTR(v), RSTRING_LEN(v), &pfamily) == -1)
        rb_raise(rb_eTypeError, "unexpected protocol family");

    v = rb_ary_entry(ary, 3);
    if (v == INT2FIX(0))
        socktype = 0;
    else {
        StringValue(v);
        if (rsock_socktype_to_int(RSTRING_PTR(v), RSTRING_LEN(v), &socktype) == -1)
            rb_raise(rb_eTypeError, "unexpected socktype");
    }

    v = rb_ary_entry(ary, 4);
    if (v == INT2FIX(0))
        protocol = 0;
    else {
        StringValue(v);
        if (IS_IP_FAMILY(afamily)) {
            if (rsock_ipproto_to_int(RSTRING_PTR(v), RSTRING_LEN(v), &protocol) == -1)
                rb_raise(rb_eTypeError, "unexpected protocol");
        }
        else {
            rb_raise(rb_eTypeError, "unexpected protocol");
        }
    }

    v = rb_ary_entry(ary, 5);
    if (NIL_P(v))
        canonname = Qnil;
    else {
        StringValue(v);
        canonname = v;
    }

    v = rb_ary_entry(ary, 6);
    if (NIL_P(v))
        inspectname = Qnil;
    else {
        StringValue(v);
        inspectname = v;
    }

    v = rb_ary_entry(ary, 1);
    switch(afamily) {
#ifdef HAVE_SYS_UN_H
      case AF_UNIX:
      {
        struct sockaddr_un uaddr;
        INIT_SOCKADDR_UN(&uaddr, sizeof(struct sockaddr_un));

        StringValue(v);
        if (sizeof(uaddr.sun_path) < (size_t)RSTRING_LEN(v))
            rb_raise(rb_eSocket,
                "too long AF_UNIX path (%"PRIuSIZE" bytes given but %"PRIuSIZE" bytes max)",
                (size_t)RSTRING_LEN(v), sizeof(uaddr.sun_path));
        memcpy(uaddr.sun_path, RSTRING_PTR(v), RSTRING_LEN(v));
        len = (socklen_t)sizeof(uaddr);
        memcpy(&ss, &uaddr, len);
        break;
      }
#endif

      default:
      {
        VALUE pair = rb_convert_type(v, T_ARRAY, "Array", "to_ary");
        struct rb_addrinfo *res;
        int flags = AI_NUMERICHOST;
#ifdef AI_NUMERICSERV
        flags |= AI_NUMERICSERV;
#endif
        res = call_getaddrinfo(rb_ary_entry(pair, 0), rb_ary_entry(pair, 1),
                               INT2NUM(pfamily), INT2NUM(socktype), INT2NUM(protocol),
                               INT2NUM(flags), 1);

        len = res->ai->ai_addrlen;
        memcpy(&ss, res->ai->ai_addr, res->ai->ai_addrlen);
        break;
      }
    }

    DATA_PTR(self) = rai = alloc_addrinfo();
    init_addrinfo(rai, &ss.addr, len,
                  pfamily, socktype, protocol,
                  canonname, inspectname);
    return self;
}

/*
 * call-seq:
 *   addrinfo.afamily => integer
 *
 * returns the address family as an integer.
 *
 *   Addrinfo.tcp("localhost", 80).afamily == Socket::AF_INET #=> true
 *
 */
static VALUE
addrinfo_afamily(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    return INT2NUM(ai_get_afamily(rai));
}

/*
 * call-seq:
 *   addrinfo.pfamily => integer
 *
 * returns the protocol family as an integer.
 *
 *   Addrinfo.tcp("localhost", 80).pfamily == Socket::PF_INET #=> true
 *
 */
static VALUE
addrinfo_pfamily(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    return INT2NUM(rai->pfamily);
}

/*
 * call-seq:
 *   addrinfo.socktype => integer
 *
 * returns the socket type as an integer.
 *
 *   Addrinfo.tcp("localhost", 80).socktype == Socket::SOCK_STREAM #=> true
 *
 */
static VALUE
addrinfo_socktype(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    return INT2NUM(rai->socktype);
}

/*
 * call-seq:
 *   addrinfo.protocol => integer
 *
 * returns the socket type as an integer.
 *
 *   Addrinfo.tcp("localhost", 80).protocol == Socket::IPPROTO_TCP #=> true
 *
 */
static VALUE
addrinfo_protocol(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    return INT2NUM(rai->protocol);
}

/*
 * call-seq:
 *   addrinfo.to_sockaddr => string
 *   addrinfo.to_s => string
 *
 * returns the socket address as packed struct sockaddr string.
 *
 *   Addrinfo.tcp("localhost", 80).to_sockaddr
 *   #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"
 *
 */
static VALUE
addrinfo_to_sockaddr(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    VALUE ret;
    ret = rb_str_new((char*)&rai->addr, rai->sockaddr_len);
    OBJ_INFECT(ret, self);
    return ret;
}

/*
 * call-seq:
 *   addrinfo.canonname => string or nil
 *
 * returns the canonical name as an string.
 *
 * nil is returned if no canonical name.
 *
 * The canonical name is set by Addrinfo.getaddrinfo when AI_CANONNAME is specified.
 *
 *   list = Addrinfo.getaddrinfo("www.ruby-lang.org", 80, :INET, :STREAM, nil, Socket::AI_CANONNAME)
 *   p list[0] #=> #<Addrinfo: 221.186.184.68:80 TCP carbon.ruby-lang.org (www.ruby-lang.org)>
 *   p list[0].canonname #=> "carbon.ruby-lang.org"
 *
 */
static VALUE
addrinfo_canonname(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    return rai->canonname;
}

/*
 * call-seq:
 *   addrinfo.ip? => true or false
 *
 * returns true if addrinfo is internet (IPv4/IPv6) address.
 * returns false otherwise.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).ip? #=> true
 *   Addrinfo.tcp("::1", 80).ip?       #=> true
 *   Addrinfo.unix("/tmp/sock").ip?    #=> false
 *
 */
static VALUE
addrinfo_ip_p(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    return IS_IP_FAMILY(family) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *   addrinfo.ipv4? => true or false
 *
 * returns true if addrinfo is IPv4 address.
 * returns false otherwise.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).ipv4? #=> true
 *   Addrinfo.tcp("::1", 80).ipv4?       #=> false
 *   Addrinfo.unix("/tmp/sock").ipv4?    #=> false
 *
 */
static VALUE
addrinfo_ipv4_p(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    return ai_get_afamily(rai) == AF_INET ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *   addrinfo.ipv6? => true or false
 *
 * returns true if addrinfo is IPv6 address.
 * returns false otherwise.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).ipv6? #=> false
 *   Addrinfo.tcp("::1", 80).ipv6?       #=> true
 *   Addrinfo.unix("/tmp/sock").ipv6?    #=> false
 *
 */
static VALUE
addrinfo_ipv6_p(VALUE self)
{
#ifdef AF_INET6
    rb_addrinfo_t *rai = get_addrinfo(self);
    return ai_get_afamily(rai) == AF_INET6 ? Qtrue : Qfalse;
#else
    return Qfalse;
#endif
}

/*
 * call-seq:
 *   addrinfo.unix? => true or false
 *
 * returns true if addrinfo is UNIX address.
 * returns false otherwise.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).unix? #=> false
 *   Addrinfo.tcp("::1", 80).unix?       #=> false
 *   Addrinfo.unix("/tmp/sock").unix?    #=> true
 *
 */
static VALUE
addrinfo_unix_p(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
#ifdef AF_UNIX
    return ai_get_afamily(rai) == AF_UNIX ? Qtrue : Qfalse;
#else
    return Qfalse;
#endif
}

/*
 * call-seq:
 *   addrinfo.getnameinfo        => [nodename, service]
 *   addrinfo.getnameinfo(flags) => [nodename, service]
 *
 * returns nodename and service as a pair of strings.
 * This converts struct sockaddr in addrinfo to textual representation.
 *
 * flags should be bitwise OR of Socket::NI_??? constants.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).getnameinfo #=> ["localhost", "www"]
 *
 *   Addrinfo.tcp("127.0.0.1", 80).getnameinfo(Socket::NI_NUMERICSERV)
 *   #=> ["localhost", "80"]
 */
static VALUE
addrinfo_getnameinfo(int argc, VALUE *argv, VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    VALUE vflags;
    char hbuf[1024], pbuf[1024];
    int flags, error;

    rb_scan_args(argc, argv, "01", &vflags);

    flags = NIL_P(vflags) ? 0 : NUM2INT(vflags);

    if (rai->socktype == SOCK_DGRAM)
        flags |= NI_DGRAM;

    error = getnameinfo(&rai->addr.addr, rai->sockaddr_len,
                        hbuf, (socklen_t)sizeof(hbuf), pbuf, (socklen_t)sizeof(pbuf),
                        flags);
    if (error) {
        rsock_raise_socket_error("getnameinfo", error);
    }

    return rb_assoc_new(rb_str_new2(hbuf), rb_str_new2(pbuf));
}

/*
 * call-seq:
 *   addrinfo.ip_unpack => [addr, port]
 *
 * Returns the IP address and port number as 2-element array.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).ip_unpack    #=> ["127.0.0.1", 80]
 *   Addrinfo.tcp("::1", 80).ip_unpack          #=> ["::1", 80]
 */
static VALUE
addrinfo_ip_unpack(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    VALUE vflags;
    VALUE ret, portstr;

    if (!IS_IP_FAMILY(family))
	rb_raise(rb_eSocket, "need IPv4 or IPv6 address");

    vflags = INT2NUM(NI_NUMERICHOST|NI_NUMERICSERV);
    ret = addrinfo_getnameinfo(1, &vflags, self);
    portstr = rb_ary_entry(ret, 1);
    rb_ary_store(ret, 1, INT2NUM(atoi(StringValueCStr(portstr))));
    return ret;
}

/*
 * call-seq:
 *   addrinfo.ip_address => string
 *
 * Returns the IP address as a string.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).ip_address    #=> "127.0.0.1"
 *   Addrinfo.tcp("::1", 80).ip_address          #=> "::1"
 */
static VALUE
addrinfo_ip_address(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    VALUE vflags;
    VALUE ret;

    if (!IS_IP_FAMILY(family))
	rb_raise(rb_eSocket, "need IPv4 or IPv6 address");

    vflags = INT2NUM(NI_NUMERICHOST|NI_NUMERICSERV);
    ret = addrinfo_getnameinfo(1, &vflags, self);
    return rb_ary_entry(ret, 0);
}

/*
 * call-seq:
 *   addrinfo.ip_port => port
 *
 * Returns the port number as an integer.
 *
 *   Addrinfo.tcp("127.0.0.1", 80).ip_port    #=> 80
 *   Addrinfo.tcp("::1", 80).ip_port          #=> 80
 */
static VALUE
addrinfo_ip_port(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    int port;

    if (!IS_IP_FAMILY(family)) {
      bad_family:
#ifdef AF_INET6
	rb_raise(rb_eSocket, "need IPv4 or IPv6 address");
#else
	rb_raise(rb_eSocket, "need IPv4 address");
#endif
    }

    switch (family) {
      case AF_INET:
        if (rai->sockaddr_len != sizeof(struct sockaddr_in))
            rb_raise(rb_eSocket, "unexpected sockaddr size for IPv4");
        port = ntohs(rai->addr.in.sin_port);
        break;

#ifdef AF_INET6
      case AF_INET6:
        if (rai->sockaddr_len != sizeof(struct sockaddr_in6))
            rb_raise(rb_eSocket, "unexpected sockaddr size for IPv6");
        port = ntohs(rai->addr.in6.sin6_port);
        break;
#endif

      default:
	goto bad_family;
    }

    return INT2NUM(port);
}

static int
extract_in_addr(VALUE self, uint32_t *addrp)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    if (family != AF_INET) return 0;
    *addrp = ntohl(rai->addr.in.sin_addr.s_addr);
    return 1;
}

/*
 * Returns true for IPv4 private address (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv4_private_p(VALUE self)
{
    uint32_t a;
    if (!extract_in_addr(self, &a)) return Qfalse;
    if ((a & 0xff000000) == 0x0a000000 || /* 10.0.0.0/8 */
        (a & 0xfff00000) == 0xac100000 || /* 172.16.0.0/12 */
        (a & 0xffff0000) == 0xc0a80000)   /* 192.168.0.0/16 */
        return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv4 loopback address (127.0.0.0/8).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv4_loopback_p(VALUE self)
{
    uint32_t a;
    if (!extract_in_addr(self, &a)) return Qfalse;
    if ((a & 0xff000000) == 0x7f000000) /* 127.0.0.0/8 */
        return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv4 multicast address (224.0.0.0/4).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv4_multicast_p(VALUE self)
{
    uint32_t a;
    if (!extract_in_addr(self, &a)) return Qfalse;
    if ((a & 0xf0000000) == 0xe0000000) /* 224.0.0.0/4 */
        return Qtrue;
    return Qfalse;
}

#ifdef INET6

static struct in6_addr *
extract_in6_addr(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    if (family != AF_INET6) return NULL;
    return &rai->addr.in6.sin6_addr;
}

/*
 * Returns true for IPv6 unspecified address (::).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_unspecified_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_UNSPECIFIED(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 loopback address (::1).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_loopback_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_LOOPBACK(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 multicast address (ff00::/8).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_multicast_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_MULTICAST(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 link local address (ff80::/10).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_linklocal_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_LINKLOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 site local address (ffc0::/10).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_sitelocal_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_SITELOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 unique local address (fc00::/7, RFC4193).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_unique_local_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_UNIQUE_LOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv4-mapped IPv6 address (::ffff:0:0/80).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_v4mapped_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_V4MAPPED(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv4-compatible IPv6 address (::/80).
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_v4compat_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_V4COMPAT(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 multicast node-local scope address.
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_mc_nodelocal_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_MC_NODELOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 multicast link-local scope address.
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_mc_linklocal_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_MC_LINKLOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 multicast site-local scope address.
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_mc_sitelocal_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_MC_SITELOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 multicast organization-local scope address.
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_mc_orglocal_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_MC_ORGLOCAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns true for IPv6 multicast global scope address.
 * It returns false otherwise.
 */
static VALUE
addrinfo_ipv6_mc_global_p(VALUE self)
{
    struct in6_addr *addr = extract_in6_addr(self);
    if (addr && IN6_IS_ADDR_MC_GLOBAL(addr)) return Qtrue;
    return Qfalse;
}

/*
 * Returns IPv4 address of IPv4 mapped/compatible IPv6 address.
 * It returns nil if +self+ is not IPv4 mapped/compatible IPv6 address.
 *
 *   Addrinfo.ip("::192.0.2.3").ipv6_to_ipv4      #=> #<Addrinfo: 192.0.2.3>
 *   Addrinfo.ip("::ffff:192.0.2.3").ipv6_to_ipv4 #=> #<Addrinfo: 192.0.2.3>
 *   Addrinfo.ip("::1").ipv6_to_ipv4              #=> nil
 *   Addrinfo.ip("192.0.2.3").ipv6_to_ipv4        #=> nil
 *   Addrinfo.unix("/tmp/sock").ipv6_to_ipv4      #=> nil
 */
static VALUE
addrinfo_ipv6_to_ipv4(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    struct in6_addr *addr;
    int family = ai_get_afamily(rai);
    if (family != AF_INET6) return Qnil;
    addr = &rai->addr.in6.sin6_addr;
    if (IN6_IS_ADDR_V4MAPPED(addr) || IN6_IS_ADDR_V4COMPAT(addr)) {
        struct sockaddr_in sin4;
        INIT_SOCKADDR_IN(&sin4, sizeof(sin4));
        memcpy(&sin4.sin_addr, (char*)addr + sizeof(*addr) - sizeof(sin4.sin_addr), sizeof(sin4.sin_addr));
        return rsock_addrinfo_new((struct sockaddr *)&sin4, (socklen_t)sizeof(sin4),
                                  PF_INET, rai->socktype, rai->protocol,
                                  rai->canonname, rai->inspectname);
    }
    else {
        return Qnil;
    }
}

#endif

#ifdef HAVE_SYS_UN_H
/*
 * call-seq:
 *   addrinfo.unix_path => path
 *
 * Returns the socket path as a string.
 *
 *   Addrinfo.unix("/tmp/sock").unix_path       #=> "/tmp/sock"
 */
static VALUE
addrinfo_unix_path(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    struct sockaddr_un *addr;
    char *s, *e;

    if (family != AF_UNIX)
	rb_raise(rb_eSocket, "need AF_UNIX address");

    addr = &rai->addr.un;

    s = addr->sun_path;
    e = (char*)addr + rai->sockaddr_len;
    if (e < s)
        rb_raise(rb_eSocket, "too short AF_UNIX address: %"PRIuSIZE" bytes given for minimum %"PRIuSIZE" bytes.",
            (size_t)rai->sockaddr_len, (size_t)(s - (char *)addr));
    if (addr->sun_path + sizeof(addr->sun_path) < e)
        rb_raise(rb_eSocket,
            "too long AF_UNIX path (%"PRIuSIZE" bytes given but %"PRIuSIZE" bytes max)",
            (size_t)(e - addr->sun_path), sizeof(addr->sun_path));
    while (s < e && *(e-1) == '\0')
        e--;
    return rb_str_new(s, e-s);
}
#endif

/*
 * call-seq:
 *   Addrinfo.getaddrinfo(nodename, service, family, socktype, protocol, flags) => [addrinfo, ...]
 *   Addrinfo.getaddrinfo(nodename, service, family, socktype, protocol)        => [addrinfo, ...]
 *   Addrinfo.getaddrinfo(nodename, service, family, socktype)                  => [addrinfo, ...]
 *   Addrinfo.getaddrinfo(nodename, service, family)                            => [addrinfo, ...]
 *   Addrinfo.getaddrinfo(nodename, service)                                    => [addrinfo, ...]
 *
 * returns a list of addrinfo objects as an array.
 *
 * This method converts nodename (hostname) and service (port) to addrinfo.
 * Since the conversion is not unique, the result is a list of addrinfo objects.
 *
 * nodename or service can be nil if no conversion intended.
 *
 * family, socktype and protocol are hint for preferred protocol.
 * If the result will be used for a socket with SOCK_STREAM,
 * SOCK_STREAM should be specified as socktype.
 * If so, Addrinfo.getaddrinfo returns addrinfo list appropriate for SOCK_STREAM.
 * If they are omitted or nil is given, the result is not restricted.
 *
 * Similarly, PF_INET6 as family restricts for IPv6.
 *
 * flags should be bitwise OR of Socket::AI_??? constants such as follows.
 * Note that the exact list of the constants depends on OS.
 *
 *   AI_PASSIVE      Get address to use with bind()
 *   AI_CANONNAME    Fill in the canonical name
 *   AI_NUMERICHOST  Prevent host name resolution
 *   AI_NUMERICSERV  Prevent service name resolution
 *   AI_V4MAPPED     Accept IPv4-mapped IPv6 addresses
 *   AI_ALL          Allow all addresses
 *   AI_ADDRCONFIG   Accept only if any address is assigned
 *
 * Note that socktype should be specified whenever application knows the usage of the address.
 * Some platform causes an error when socktype is omitted and servname is specified as an integer
 * because some port numbers, 512 for example, are ambiguous without socktype.
 *
 *   Addrinfo.getaddrinfo("www.kame.net", 80, nil, :STREAM)
 *   #=> [#<Addrinfo: 203.178.141.194:80 TCP (www.kame.net)>,
 *   #    #<Addrinfo: [2001:200:dff:fff1:216:3eff:feb1:44d7]:80 TCP (www.kame.net)>]
 *
 */
static VALUE
addrinfo_s_getaddrinfo(int argc, VALUE *argv, VALUE self)
{
    VALUE node, service, family, socktype, protocol, flags;

    rb_scan_args(argc, argv, "24", &node, &service, &family, &socktype, &protocol, &flags);
    return addrinfo_list_new(node, service, family, socktype, protocol, flags);
}

/*
 * call-seq:
 *   Addrinfo.ip(host) => addrinfo
 *
 * returns an addrinfo object for IP address.
 *
 * The port, socktype, protocol of the result is filled by zero.
 * So, it is not appropriate to create a socket.
 *
 *   Addrinfo.ip("localhost") #=> #<Addrinfo: 127.0.0.1 (localhost)>
 */
static VALUE
addrinfo_s_ip(VALUE self, VALUE host)
{
    VALUE ret;
    rb_addrinfo_t *rai;
    ret = addrinfo_firstonly_new(host, Qnil,
            INT2NUM(PF_UNSPEC), INT2FIX(0), INT2FIX(0), INT2FIX(0));
    rai = get_addrinfo(ret);
    rai->socktype = 0;
    rai->protocol = 0;
    return ret;
}

/*
 * call-seq:
 *   Addrinfo.tcp(host, port) => addrinfo
 *
 * returns an addrinfo object for TCP address.
 *
 *   Addrinfo.tcp("localhost", "smtp") #=> #<Addrinfo: 127.0.0.1:25 TCP (localhost:smtp)>
 */
static VALUE
addrinfo_s_tcp(VALUE self, VALUE host, VALUE port)
{
    return addrinfo_firstonly_new(host, port,
            INT2NUM(PF_UNSPEC), INT2NUM(SOCK_STREAM), INT2NUM(IPPROTO_TCP), INT2FIX(0));
}

/*
 * call-seq:
 *   Addrinfo.udp(host, port) => addrinfo
 *
 * returns an addrinfo object for UDP address.
 *
 *   Addrinfo.udp("localhost", "daytime") #=> #<Addrinfo: 127.0.0.1:13 UDP (localhost:daytime)>
 */
static VALUE
addrinfo_s_udp(VALUE self, VALUE host, VALUE port)
{
    return addrinfo_firstonly_new(host, port,
            INT2NUM(PF_UNSPEC), INT2NUM(SOCK_DGRAM), INT2NUM(IPPROTO_UDP), INT2FIX(0));
}

#ifdef HAVE_SYS_UN_H

/*
 * call-seq:
 *   Addrinfo.unix(path [, socktype]) => addrinfo
 *
 * returns an addrinfo object for UNIX socket address.
 *
 * _socktype_ specifies the socket type.
 * If it is omitted, :STREAM is used.
 *
 *   Addrinfo.unix("/tmp/sock")         #=> #<Addrinfo: /tmp/sock SOCK_STREAM>
 *   Addrinfo.unix("/tmp/sock", :DGRAM) #=> #<Addrinfo: /tmp/sock SOCK_DGRAM>
 */
static VALUE
addrinfo_s_unix(int argc, VALUE *argv, VALUE self)
{
    VALUE path, vsocktype, addr;
    int socktype;
    rb_addrinfo_t *rai;

    rb_scan_args(argc, argv, "11", &path, &vsocktype);

    if (NIL_P(vsocktype))
        socktype = SOCK_STREAM;
    else
        socktype = rsock_socktype_arg(vsocktype);

    addr = addrinfo_s_allocate(rb_cAddrinfo);
    DATA_PTR(addr) = rai = alloc_addrinfo();
    init_unix_addrinfo(rai, path, socktype);
    OBJ_INFECT(addr, path);
    return addr;
}

#endif

VALUE
rsock_sockaddr_string_value(volatile VALUE *v)
{
    VALUE val = *v;
    if (IS_ADDRINFO(val)) {
        *v = addrinfo_to_sockaddr(val);
    }
    StringValue(*v);
    return *v;
}

VALUE
rsock_sockaddr_string_value_with_addrinfo(volatile VALUE *v, VALUE *rai_ret)
{
    VALUE val = *v;
    *rai_ret = Qnil;
    if (IS_ADDRINFO(val)) {
        *v = addrinfo_to_sockaddr(val);
        *rai_ret = val;
    }
    StringValue(*v);
    return *v;
}

char *
rsock_sockaddr_string_value_ptr(volatile VALUE *v)
{
    rsock_sockaddr_string_value(v);
    return RSTRING_PTR(*v);
}

VALUE
rb_check_sockaddr_string_type(VALUE val)
{
    if (IS_ADDRINFO(val))
        return addrinfo_to_sockaddr(val);
    return rb_check_string_type(val);
}

VALUE
rsock_fd_socket_addrinfo(int fd, struct sockaddr *addr, socklen_t len)
{
    int family;
    int socktype;
    int ret;
    socklen_t optlen = (socklen_t)sizeof(socktype);

    /* assumes protocol family and address family are identical */
    family = get_afamily(addr, len);

    ret = getsockopt(fd, SOL_SOCKET, SO_TYPE, (void*)&socktype, &optlen);
    if (ret == -1) {
        rb_sys_fail("getsockopt(SO_TYPE)");
    }

    return rsock_addrinfo_new(addr, len, family, socktype, 0, Qnil, Qnil);
}

VALUE
rsock_io_socket_addrinfo(VALUE io, struct sockaddr *addr, socklen_t len)
{
    rb_io_t *fptr;

    switch (TYPE(io)) {
      case T_FIXNUM:
        return rsock_fd_socket_addrinfo(FIX2INT(io), addr, len);

      case T_BIGNUM:
        return rsock_fd_socket_addrinfo(NUM2INT(io), addr, len);

      case T_FILE:
        GetOpenFile(io, fptr);
        return rsock_fd_socket_addrinfo(fptr->fd, addr, len);

      default:
        rb_raise(rb_eTypeError, "neither IO nor file descriptor");
    }

    UNREACHABLE;
}

/*
 * Addrinfo class
 */
void
rsock_init_addrinfo(void)
{
    /*
     * The Addrinfo class maps <tt>struct addrinfo</tt> to ruby.  This
     * structure identifies an Internet host and a service.
     */
    rb_cAddrinfo = rb_define_class("Addrinfo", rb_cData);
    rb_define_alloc_func(rb_cAddrinfo, addrinfo_s_allocate);
    rb_define_method(rb_cAddrinfo, "initialize", addrinfo_initialize, -1);
    rb_define_method(rb_cAddrinfo, "inspect", addrinfo_inspect, 0);
    rb_define_method(rb_cAddrinfo, "inspect_sockaddr", rsock_addrinfo_inspect_sockaddr, 0);
    rb_define_singleton_method(rb_cAddrinfo, "getaddrinfo", addrinfo_s_getaddrinfo, -1);
    rb_define_singleton_method(rb_cAddrinfo, "ip", addrinfo_s_ip, 1);
    rb_define_singleton_method(rb_cAddrinfo, "tcp", addrinfo_s_tcp, 2);
    rb_define_singleton_method(rb_cAddrinfo, "udp", addrinfo_s_udp, 2);
#ifdef HAVE_SYS_UN_H
    rb_define_singleton_method(rb_cAddrinfo, "unix", addrinfo_s_unix, -1);
#endif

    rb_define_method(rb_cAddrinfo, "afamily", addrinfo_afamily, 0);
    rb_define_method(rb_cAddrinfo, "pfamily", addrinfo_pfamily, 0);
    rb_define_method(rb_cAddrinfo, "socktype", addrinfo_socktype, 0);
    rb_define_method(rb_cAddrinfo, "protocol", addrinfo_protocol, 0);
    rb_define_method(rb_cAddrinfo, "canonname", addrinfo_canonname, 0);

    rb_define_method(rb_cAddrinfo, "ipv4?", addrinfo_ipv4_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6?", addrinfo_ipv6_p, 0);
    rb_define_method(rb_cAddrinfo, "unix?", addrinfo_unix_p, 0);

    rb_define_method(rb_cAddrinfo, "ip?", addrinfo_ip_p, 0);
    rb_define_method(rb_cAddrinfo, "ip_unpack", addrinfo_ip_unpack, 0);
    rb_define_method(rb_cAddrinfo, "ip_address", addrinfo_ip_address, 0);
    rb_define_method(rb_cAddrinfo, "ip_port", addrinfo_ip_port, 0);

    rb_define_method(rb_cAddrinfo, "ipv4_private?", addrinfo_ipv4_private_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv4_loopback?", addrinfo_ipv4_loopback_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv4_multicast?", addrinfo_ipv4_multicast_p, 0);

#ifdef INET6
    rb_define_method(rb_cAddrinfo, "ipv6_unspecified?", addrinfo_ipv6_unspecified_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_loopback?", addrinfo_ipv6_loopback_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_multicast?", addrinfo_ipv6_multicast_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_linklocal?", addrinfo_ipv6_linklocal_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_sitelocal?", addrinfo_ipv6_sitelocal_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_unique_local?", addrinfo_ipv6_unique_local_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_v4mapped?", addrinfo_ipv6_v4mapped_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_v4compat?", addrinfo_ipv6_v4compat_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_mc_nodelocal?", addrinfo_ipv6_mc_nodelocal_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_mc_linklocal?", addrinfo_ipv6_mc_linklocal_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_mc_sitelocal?", addrinfo_ipv6_mc_sitelocal_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_mc_orglocal?", addrinfo_ipv6_mc_orglocal_p, 0);
    rb_define_method(rb_cAddrinfo, "ipv6_mc_global?", addrinfo_ipv6_mc_global_p, 0);

    rb_define_method(rb_cAddrinfo, "ipv6_to_ipv4", addrinfo_ipv6_to_ipv4, 0);
#endif

#ifdef HAVE_SYS_UN_H
    rb_define_method(rb_cAddrinfo, "unix_path", addrinfo_unix_path, 0);
#endif

    rb_define_method(rb_cAddrinfo, "to_sockaddr", addrinfo_to_sockaddr, 0);
    rb_define_method(rb_cAddrinfo, "to_s", addrinfo_to_sockaddr, 0); /* compatibility for ruby before 1.9.2 */

    rb_define_method(rb_cAddrinfo, "getnameinfo", addrinfo_getnameinfo, -1);

    rb_define_method(rb_cAddrinfo, "marshal_dump", addrinfo_mdump, 0);
    rb_define_method(rb_cAddrinfo, "marshal_load", addrinfo_mload, 1);
}