summaryrefslogtreecommitdiffstats
path: root/src/resolvers.c
blob: 47b0cce44d356e7da3d635a2d82444ca6f5e2d8a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
/*
 * Name server resolution
 *
 * Copyright 2014 Baptiste Assmann <bedis9@gmail.com>
 *
 * 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.
 *
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/types.h>

#include <import/ebistree.h>

#include <haproxy/action.h>
#include <haproxy/api.h>
#include <haproxy/applet.h>
#include <haproxy/cfgparse.h>
#include <haproxy/channel.h>
#include <haproxy/check.h>
#include <haproxy/cli.h>
#include <haproxy/dns.h>
#include <haproxy/dns_ring.h>
#include <haproxy/errors.h>
#include <haproxy/fd.h>
#include <haproxy/http_rules.h>
#include <haproxy/log.h>
#include <haproxy/net_helper.h>
#include <haproxy/protocol.h>
#include <haproxy/proxy.h>
#include <haproxy/resolvers.h>
#include <haproxy/sample.h>
#include <haproxy/sc_strm.h>
#include <haproxy/server.h>
#include <haproxy/stats.h>
#include <haproxy/stconn.h>
#include <haproxy/task.h>
#include <haproxy/tcp_rules.h>
#include <haproxy/ticks.h>
#include <haproxy/time.h>
#include <haproxy/tools.h>
#include <haproxy/vars.h>
#include <haproxy/xxhash.h>

#if defined(USE_PROMEX)
#include <promex/promex.h>
#endif


struct list sec_resolvers  = LIST_HEAD_INIT(sec_resolvers);
struct list resolv_srvrq_list = LIST_HEAD_INIT(resolv_srvrq_list);

static THREAD_LOCAL struct list death_row; /* list of deferred resolutions to kill, local validity only */
static THREAD_LOCAL unsigned int recurse = 0; /* counter to track calls to public functions */
static THREAD_LOCAL uint64_t resolv_query_id_seed = 0; /* random seed */
struct resolvers *curr_resolvers = NULL;

DECLARE_STATIC_POOL(resolv_answer_item_pool, "resolv_answer_item", sizeof(struct resolv_answer_item));
DECLARE_STATIC_POOL(resolv_resolution_pool,  "resolv_resolution",  sizeof(struct resolv_resolution));
DECLARE_POOL(resolv_requester_pool,  "resolv_requester",  sizeof(struct resolv_requester));

static unsigned int resolution_uuid = 1;
unsigned int resolv_failed_resolutions = 0;
struct task *process_resolvers(struct task *t, void *context, unsigned int state);
static void resolv_free_resolution(struct resolv_resolution *resolution);
static void _resolv_unlink_resolution(struct resolv_requester *requester);
static void enter_resolver_code();
static void leave_resolver_code();

enum {
	RSLV_STAT_ID,
	RSLV_STAT_PID,
	RSLV_STAT_SENT,
	RSLV_STAT_SND_ERROR,
	RSLV_STAT_VALID,
	RSLV_STAT_UPDATE,
	RSLV_STAT_CNAME,
	RSLV_STAT_CNAME_ERROR,
	RSLV_STAT_ANY_ERR,
	RSLV_STAT_NX,
	RSLV_STAT_TIMEOUT,
	RSLV_STAT_REFUSED,
	RSLV_STAT_OTHER,
	RSLV_STAT_INVALID,
	RSLV_STAT_TOO_BIG,
	RSLV_STAT_TRUNCATED,
	RSLV_STAT_OUTDATED,
	RSLV_STAT_END,
};

static struct stat_col resolv_stats[] = {
	[RSLV_STAT_ID]          = { .name = "id",          .desc = "ID" },
	[RSLV_STAT_PID]         = { .name = "pid",         .desc = "Parent ID" },
	[RSLV_STAT_SENT]        = { .name = "sent",        .desc = "Sent" },
	[RSLV_STAT_SND_ERROR]   = { .name = "send_error",  .desc = "Send error" },
	[RSLV_STAT_VALID]       = { .name = "valid",       .desc = "Valid" },
	[RSLV_STAT_UPDATE]      = { .name = "update",      .desc = "Update" },
	[RSLV_STAT_CNAME]       = { .name = "cname",       .desc = "CNAME" },
	[RSLV_STAT_CNAME_ERROR] = { .name = "cname_error", .desc = "CNAME error" },
	[RSLV_STAT_ANY_ERR]     = { .name = "any_err",     .desc = "Any errors" },
	[RSLV_STAT_NX]          = { .name = "nx",          .desc = "NX" },
	[RSLV_STAT_TIMEOUT]     = { .name = "timeout",     .desc = "Timeout" },
	[RSLV_STAT_REFUSED]     = { .name = "refused",     .desc = "Refused" },
	[RSLV_STAT_OTHER]       = { .name = "other",       .desc = "Other" },
	[RSLV_STAT_INVALID]     = { .name = "invalid",     .desc = "Invalid" },
	[RSLV_STAT_TOO_BIG]     = { .name = "too_big",     .desc = "Too big" },
	[RSLV_STAT_TRUNCATED]   = { .name = "truncated",   .desc = "Truncated" },
	[RSLV_STAT_OUTDATED]    = { .name = "outdated",    .desc = "Outdated" },
};

static struct dns_counters dns_counters;

static int resolv_fill_stats(void *d, struct field *stats, unsigned int *selected_field)
{
	struct dns_counters *counters = d;
	unsigned int current_field = (selected_field != NULL ? *selected_field : 0);

	for (; current_field < RSLV_STAT_END; current_field++) {
		struct field metric = { 0 };

		switch (current_field) {
		case RSLV_STAT_ID:
			metric = mkf_str(FO_CONFIG, counters->id);
			break;
		case RSLV_STAT_PID:
			metric = mkf_str(FO_CONFIG, counters->pid);
			break;
		case RSLV_STAT_SENT:
			metric = mkf_u64(FN_GAUGE, counters->sent);
			break;
		case RSLV_STAT_SND_ERROR:
			metric = mkf_u64(FN_GAUGE, counters->snd_error);
			break;
		case RSLV_STAT_VALID:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.valid);
			break;
		case RSLV_STAT_UPDATE:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.update);
			break;
		case RSLV_STAT_CNAME:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.cname);
			break;
		case RSLV_STAT_CNAME_ERROR:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.cname_error);
			break;
		case RSLV_STAT_ANY_ERR:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.any_err);
			break;
		case RSLV_STAT_NX:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.nx);
			break;
		case RSLV_STAT_TIMEOUT:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.timeout);
			break;
		case RSLV_STAT_REFUSED:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.refused);
			break;
		case RSLV_STAT_OTHER:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.other);
			break;
		case RSLV_STAT_INVALID:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.invalid);
			break;
		case RSLV_STAT_TOO_BIG:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.too_big);
			break;
		case RSLV_STAT_TRUNCATED:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.truncated);
			break;
		case RSLV_STAT_OUTDATED:
			metric = mkf_u64(FN_GAUGE, counters->app.resolver.outdated);
			break;
		default:
			/* not used for frontends. If a specific metric
			 * is requested, return an error. Otherwise continue.
			 */
			if (selected_field != NULL)
				return 0;
			continue;
		}
		stats[current_field] = metric;
		if (selected_field != NULL)
			break;
	}
	return 1;
}

static struct stats_module rslv_stats_module = {
	.name          = "resolvers",
	.domain_flags  = STATS_DOMAIN_RESOLVERS << STATS_DOMAIN,
	.fill_stats    = resolv_fill_stats,
	.stats         = resolv_stats,
	.stats_count   = RSLV_STAT_END,
	.counters      = &dns_counters,
	.counters_size = sizeof(dns_counters),
	.clearable     = 0,
};

INITCALL1(STG_REGISTER, stats_register_module, &rslv_stats_module);

/* CLI context used during "show resolvers" */
struct show_resolvers_ctx {
	struct resolvers *forced_section;
	struct resolvers *resolvers;
	struct dns_nameserver *ns;
};

/* Returns a pointer to the resolvers matching the id <id>. NULL is returned if
 * no match is found.
 */
struct resolvers *find_resolvers_by_id(const char *id)
{
	struct resolvers *res;

	list_for_each_entry(res, &sec_resolvers, list) {
		if (strcmp(res->id, id) == 0)
			return res;
	}
	return NULL;
}

/* Returns a pointer to the nameserver matching numerical <id> within <parent>
 * resolver section. NULL is returned if no match is found.
 */
struct dns_nameserver *find_nameserver_by_resolvers_and_id(struct resolvers *parent, unsigned int id)
{
	struct dns_nameserver *ns;

	list_for_each_entry(ns, &parent->nameservers, list) {
		if (ns->puid == id)
			return ns;
	}
	return NULL;
}

/* Returns a pointer on the SRV request matching the name <name> for the proxy
 * <px>. NULL is returned if no match is found.
 */
struct resolv_srvrq *find_srvrq_by_name(const char *name, struct proxy *px)
{
	struct resolv_srvrq *srvrq;

	list_for_each_entry(srvrq, &resolv_srvrq_list, list) {
		if (srvrq->proxy == px && strcmp(srvrq->name, name) == 0)
			return srvrq;
	}
	return NULL;
}

/* Allocates a new SRVRQ for the given server with the name <fqdn>. It returns
 * NULL if an error occurred. */
struct resolv_srvrq *new_resolv_srvrq(struct server *srv, char *fqdn)
{
	struct proxy     *px    = srv->proxy;
	struct resolv_srvrq *srvrq = NULL;
	int fqdn_len, hostname_dn_len;

	fqdn_len = strlen(fqdn);
	hostname_dn_len = resolv_str_to_dn_label(fqdn, fqdn_len, trash.area,
					      trash.size);
	if (hostname_dn_len == -1) {
		ha_alert("%s '%s', server '%s': failed to parse FQDN '%s'\n",
			 proxy_type_str(px), px->id, srv->id, fqdn);
		goto err;
	}

	if ((srvrq = calloc(1, sizeof(*srvrq))) == NULL) {
		ha_alert("%s '%s', server '%s': out of memory\n",
			 proxy_type_str(px), px->id, srv->id);
		goto err;
	}
	srvrq->obj_type        = OBJ_TYPE_SRVRQ;
	srvrq->proxy           = px;
	srvrq->name            = strdup(fqdn);
	srvrq->hostname_dn     = strdup(trash.area);
	srvrq->hostname_dn_len = hostname_dn_len;
	if (!srvrq->name || !srvrq->hostname_dn) {
		ha_alert("%s '%s', server '%s': out of memory\n",
			 proxy_type_str(px), px->id, srv->id);
		goto err;
	}
	LIST_INIT(&srvrq->attached_servers);
	srvrq->named_servers = EB_ROOT;
	LIST_APPEND(&resolv_srvrq_list, &srvrq->list);
	return srvrq;

  err:
	if (srvrq) {
		free(srvrq->name);
		free(srvrq->hostname_dn);
		free(srvrq);
	}
	return NULL;
}


/* finds and return the SRV answer item associated to a requester (whose type is 'server').
 *
 * returns NULL in case of error or not found.
 */
struct resolv_answer_item *find_srvrq_answer_record(const struct resolv_requester *requester)
{
	struct resolv_resolution *res;
	struct eb32_node *eb32;
	struct server *srv;

	if (!requester)
		return NULL;

	if ((srv = objt_server(requester->owner)) == NULL)
		return NULL;
	/* check if the server is managed by a SRV record */
	if (srv->srvrq == NULL)
		return NULL;

	res = srv->srvrq->requester->resolution;

	/* search an ANSWER record whose target points to the server's hostname and whose port is
	 * the same as server's svc_port */
	for (eb32 = eb32_first(&res->response.answer_tree); eb32 != NULL;  eb32 = eb32_next(eb32)) {
		struct resolv_answer_item *item = eb32_entry(eb32, typeof(*item), link);

		if (memcmp(srv->hostname_dn, item->data.target, srv->hostname_dn_len) == 0 &&
		    (srv->svc_port == item->port))
			return item;
	}

	return NULL;
}

/* 2 bytes random generator to generate DNS query ID */
static inline uint16_t resolv_rnd16(void)
{
	if (!resolv_query_id_seed)
		resolv_query_id_seed = now_ms;
	resolv_query_id_seed ^= resolv_query_id_seed << 13;
	resolv_query_id_seed ^= resolv_query_id_seed >> 7;
	resolv_query_id_seed ^= resolv_query_id_seed << 17;
	return resolv_query_id_seed;
}


static inline int resolv_resolution_timeout(struct resolv_resolution *res)
{
	return res->resolvers->timeout.resolve;
}

/* Updates a resolvers' task timeout for next wake up and queue it */
static void resolv_update_resolvers_timeout(struct resolvers *resolvers)
{
	struct resolv_resolution *res;
	int next = TICK_ETERNITY;

	if (!LIST_ISEMPTY(&resolvers->resolutions.curr)) {
		res  = LIST_NEXT(&resolvers->resolutions.curr, struct resolv_resolution *, list);
		next = tick_add(now_ms, resolvers->timeout.resolve);
		next = tick_first(next, tick_add(res->last_query, resolvers->timeout.retry));
	}

	list_for_each_entry(res, &resolvers->resolutions.wait, list)
		next = tick_first(next, tick_add(res->last_resolution, resolv_resolution_timeout(res)));

	resolvers->t->expire = next;
	task_queue(resolvers->t);
}

/* Forges a DNS query. It needs the following information from the caller:
 *  - <query_id>        : the DNS query id corresponding to this query
 *  - <query_type>      : DNS_RTYPE_* request DNS record type (A, AAAA, ANY...)
 *  - <hostname_dn>     : hostname in domain name format
 *  - <hostname_dn_len> : length of <hostname_dn>
 *
 * To store the query, the caller must pass a buffer <buf> and its size
 * <bufsize>. It returns the number of written bytes in success, -1 if <buf> is
 * too short.
 */
static int resolv_build_query(int query_id, int query_type, unsigned int accepted_payload_size,
                              char *hostname_dn, int hostname_dn_len, char *buf, int bufsize)
{
	struct dns_header            dns_hdr;
	struct dns_question          qinfo;
	struct dns_additional_record edns;
	char *p = buf;

	if (sizeof(dns_hdr) + sizeof(qinfo) +  sizeof(edns) + hostname_dn_len >= bufsize)
		return -1;

	memset(buf, 0, bufsize);

	/* Set dns query headers */
	dns_hdr.id      = (unsigned short) htons(query_id);
	dns_hdr.flags   = htons(0x0100); /* qr=0, opcode=0, aa=0, tc=0, rd=1, ra=0, z=0, rcode=0 */
	dns_hdr.qdcount = htons(1);      /* 1 question */
	dns_hdr.ancount = 0;
	dns_hdr.nscount = 0;
	dns_hdr.arcount = htons(1);
	memcpy(p, &dns_hdr, sizeof(dns_hdr));
	p += sizeof(dns_hdr);

	/* Set up query hostname */
	memcpy(p, hostname_dn, hostname_dn_len);
	p += hostname_dn_len;
	*p++ = 0;

	/* Set up query info (type and class) */
	qinfo.qtype  = htons(query_type);
	qinfo.qclass = htons(DNS_RCLASS_IN);
	memcpy(p, &qinfo, sizeof(qinfo));
	p += sizeof(qinfo);

	/* Set the DNS extension */
	edns.name             = 0;
	edns.type             = htons(DNS_RTYPE_OPT);
	edns.udp_payload_size = htons(accepted_payload_size);
	edns.extension        = 0;
	edns.data_length      = 0;
	memcpy(p, &edns, sizeof(edns));
	p += sizeof(edns);

	return (p - buf);
}

/* Sends a DNS query to resolvers associated to a resolution. It returns 0 on
 * success or -1 if trash buffer is not large enough to build a valid query.
 */
static int resolv_send_query(struct resolv_resolution *resolution)
{
	struct resolvers  *resolvers = resolution->resolvers;
	struct dns_nameserver *ns;
	int len;

	/* Update resolution */
	resolution->nb_queries   = 0;
	resolution->nb_responses = 0;
	resolution->last_query   = now_ms;

	len = resolv_build_query(resolution->query_id, resolution->query_type,
	                      resolvers->accepted_payload_size,
	                      resolution->hostname_dn, resolution->hostname_dn_len,
	                      trash.area, trash.size);
	if (len < 0) {
		send_log(NULL, LOG_NOTICE,
			 "can not build the query message for %s, in resolvers %s.\n",
			 resolution->hostname_dn, resolvers->id);
		return -1;
	}

	list_for_each_entry(ns, &resolvers->nameservers, list) {
		if (dns_send_nameserver(ns, trash.area, len) >= 0)
			resolution->nb_queries++;
	}

	/* Push the resolution at the end of the active list */
	LIST_DEL_INIT(&resolution->list);
	LIST_APPEND(&resolvers->resolutions.curr, &resolution->list);
	return 0;
}

/* Prepares and sends a DNS resolution. It returns 1 if the query was sent, 0 if
 * skipped and -1 if an error occurred.
 */
static int
resolv_run_resolution(struct resolv_resolution *resolution)
{
	struct resolvers  *resolvers = resolution->resolvers;
	int query_id, i;

	/* Avoid sending requests for resolutions that don't yet have an
	 * hostname, ie resolutions linked to servers that do not yet have an
	 * fqdn */
	if (!resolution->hostname_dn)
		return 0;

	/* Check if a resolution has already been started for this server return
	 * directly to avoid resolution pill up. */
	if (resolution->step != RSLV_STEP_NONE)
		return 0;

	/* Generates a new query id. We try at most 100 times to find a free
	 * query id */
	for (i = 0; i < 100; ++i) {
		query_id = resolv_rnd16();
		if (!eb32_lookup(&resolvers->query_ids, query_id))
			break;
		query_id = -1;
	}
	if (query_id == -1) {
		send_log(NULL, LOG_NOTICE,
			 "could not generate a query id for %s, in resolvers %s.\n",
			 resolution->hostname_dn, resolvers->id);
		return -1;
	}

	/* Update resolution parameters */
	resolution->query_id     = query_id;
	resolution->qid.key      = query_id;
	resolution->step         = RSLV_STEP_RUNNING;
	resolution->query_type   = resolution->prefered_query_type;
	resolution->try          = resolvers->resolve_retries;
	eb32_insert(&resolvers->query_ids, &resolution->qid);

	/* Send the DNS query */
	resolution->try -= 1;
	resolv_send_query(resolution);
	return 1;
}

/* Performs a name resolution for the requester <req> */
void resolv_trigger_resolution(struct resolv_requester *req)
{
	struct resolvers  *resolvers;
	struct resolv_resolution *res;
	int exp;

	if (!req || !req->resolution)
		return;
	res       = req->resolution;
	resolvers = res->resolvers;

	enter_resolver_code();

	/* The resolution must not be triggered yet. Use the cached response, if
	 * valid */
	exp = tick_add(res->last_resolution, resolvers->hold.valid);
	if (resolvers->t && (!tick_isset(resolvers->t->expire) || res->status != RSLV_STATUS_VALID ||
	    !tick_isset(res->last_resolution) || tick_is_expired(exp, now_ms))) {
		/* If the resolution is not running and the requester is a
		 * server, reset the resolution timer to force a quick
		 * resolution.
		 */
		if (res->step == RSLV_STEP_NONE &&
		    (obj_type(req->owner) == OBJ_TYPE_SERVER ||
		     obj_type(req->owner) == OBJ_TYPE_SRVRQ))
			res->last_resolution = TICK_ETERNITY;
		task_wakeup(resolvers->t, TASK_WOKEN_OTHER);
	}

	leave_resolver_code();
}


/* Resets some resolution parameters to initial values and also delete the query
 * ID from the resolver's tree.
 */
static void resolv_reset_resolution(struct resolv_resolution *resolution)
{
	/* update resolution status */
	resolution->step            = RSLV_STEP_NONE;
	resolution->try             = 0;
	resolution->last_resolution = now_ms;
	resolution->nb_queries      = 0;
	resolution->nb_responses    = 0;
	resolution->query_type      = resolution->prefered_query_type;

	/* clean up query id */
	eb32_delete(&resolution->qid);
	resolution->query_id = 0;
	resolution->qid.key   = 0;
}

/* Returns the query id contained in a DNS response */
static inline unsigned short resolv_response_get_query_id(unsigned char *resp)
{
	return resp[0] * 256 + resp[1];
}


/* Analyses, re-builds and copies the name <name> from the DNS response packet
 * <buffer>.  <name> must point to the 'data_len' information or pointer 'c0'
 * for compressed data.  The result is copied into <dest>, ensuring we don't
 * overflow using <dest_len> Returns the number of bytes the caller can move
 * forward. If 0 it means an error occurred while parsing the name. <offset> is
 * the number of bytes the caller could move forward.
 */
int resolv_read_name(unsigned char *buffer, unsigned char *bufend,
		     unsigned char *name, char *destination, int dest_len,
		     int *offset, unsigned int depth)
{
	int nb_bytes = 0, n = 0;
	int label_len;
	unsigned char *reader = name;
	char *dest = destination;

	while (1) {
		if (reader >= bufend)
			goto err;

		/* Name compression is in use */
		if ((*reader & 0xc0) == 0xc0) {
			if (reader + 1 >= bufend)
				goto err;

			/* Must point BEFORE current position */
			if ((buffer + reader[1]) > reader)
				goto err;

			if (depth++ > 100)
				goto err;

			n = resolv_read_name(buffer, bufend, buffer + (*reader & 0x3f)*256 + reader[1],
			                     dest, dest_len - nb_bytes, offset, depth);
			if (n == 0)
				goto err;

			dest     += n;
			nb_bytes += n;
			goto out;
		}

		label_len = *reader;
		if (label_len == 0)
			goto out;

		/* Check if:
		 *  - we won't read outside the buffer
		 *  - there is enough place in the destination
		 */
		if ((reader + label_len >= bufend) || (nb_bytes + label_len >= dest_len))
			goto err;

		/* +1 to take label len + label string */
		label_len++;

		memcpy(dest, reader, label_len);

		dest     += label_len;
		nb_bytes += label_len;
		reader   += label_len;
	}

  out:
	/* offset computation:
	 * parse from <name> until finding either NULL or a pointer "c0xx"
	 */
	reader  = name;
	*offset = 0;
	while (reader < bufend) {
		if ((reader[0] & 0xc0) == 0xc0) {
			*offset += 2;
			break;
		}
		else if (*reader == 0) {
			*offset += 1;
			break;
		}
		*offset += 1;
		++reader;
	}
	return nb_bytes;

  err:
	return 0;
}

/* Reinitialize the list of aborted resolutions before calling certain
 * functions relying on it. The list must be processed by calling
 * leave_resolver_code() after operations.
 */
static void enter_resolver_code()
{
	if (!recurse)
		LIST_INIT(&death_row);
	recurse++;
}

/* Add a resolution to the death_row. */
static void abort_resolution(struct resolv_resolution *res)
{
	/* Remove the resolution from query_ids tree and from any resolvers list */
	eb32_delete(&res->qid);
	res->query_id = 0;
	res->qid.key   = 0;

	LIST_DEL_INIT(&res->list);
	LIST_APPEND(&death_row, &res->list);
}

/* This releases any aborted resolution found in the death row. It is mandatory
 * to call enter_resolver_code() first before the function (or loop) that
 * needs to defer deletions. Note that some of them are in relation via internal
 * objects and might cause the deletion of other ones from the same list, so we
 * must absolutely not use a list_for_each_entry_safe() nor any such thing here,
 * and solely rely on each call to remove the first remaining list element.
 */
static void leave_resolver_code()
{
	struct resolv_resolution *res;

	recurse--;
	if (recurse)
		return;

	while (!LIST_ISEMPTY(&death_row)) {
		res = LIST_NEXT(&death_row, struct resolv_resolution *, list);
		resolv_free_resolution(res);
	}

	/* make sure nobody tries to add anything without having initialized it */
	death_row = (struct list){ };
}

/* Cleanup fqdn/port and address of a server attached to a SRV resolution. This
 * happens when an SRV item is purged or when the server status is considered as
 * obsolete.
 *
 * Must be called with the DNS lock held, and with the death_row already
 * initialized via enter_resolver_code().
 */
static void resolv_srvrq_cleanup_srv(struct server *srv)
{
	struct server_inetaddr srv_addr;

	_resolv_unlink_resolution(srv->resolv_requester);
	HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
	srvrq_set_srv_down(srv);
	ha_free(&srv->hostname);
	ha_free(&srv->hostname_dn);
	srv->hostname_dn_len = 0;
	memset(&srv_addr, 0, sizeof(srv_addr));
	/* unset server's addr AND port */
	server_set_inetaddr(srv, &srv_addr, SERVER_INETADDR_UPDATER_NONE, NULL);
	srv->flags |= SRV_F_NO_RESOLUTION;

	ebpt_delete(&srv->host_dn);
	ha_free(&srv->host_dn.key);

	HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
	LIST_DEL_INIT(&srv->srv_rec_item);
	LIST_APPEND(&srv->srvrq->attached_servers, &srv->srv_rec_item);

	srv->srvrq_check->expire = TICK_ETERNITY;
}

/* Takes care to cleanup a server resolution when it is outdated. This only
 * happens for a server relying on a SRV record.
 */
static struct task *resolv_srvrq_expire_task(struct task *t, void *context, unsigned int state)
{
	struct server *srv = context;

	if (!tick_is_expired(t->expire, now_ms))
		goto end;

	enter_resolver_code();
	HA_SPIN_LOCK(DNS_LOCK, &srv->srvrq->resolvers->lock);
	resolv_srvrq_cleanup_srv(srv);
	HA_SPIN_UNLOCK(DNS_LOCK, &srv->srvrq->resolvers->lock);
	leave_resolver_code();

  end:
	return t;
}

/* Checks for any obsolete record, also identify any SRV request, and try to
 * find a corresponding server.
 */
static void resolv_check_response(struct resolv_resolution *res)
{
	struct resolvers   *resolvers = res->resolvers;
	struct resolv_requester   *req;
	struct eb32_node          *eb32, *eb32_back;
	struct server          *srv, *srvback;
	struct resolv_srvrq       *srvrq;

	for (eb32 = eb32_first(&res->response.answer_tree); eb32 && (eb32_back = eb32_next(eb32), 1); eb32 = eb32_back) {
		struct resolv_answer_item *item = eb32_entry(eb32, typeof(*item), link);
		struct resolv_answer_item *ar_item = item->ar_item;

		/* clean up obsolete Additional record */
		if (ar_item && tick_is_lt(tick_add(ar_item->last_seen, resolvers->hold.obsolete), now_ms)) {
			/* Cleaning up the AR item will trigger an extra DNS  resolution, except if the SRV
			 * item is also obsolete.
			 */
			pool_free(resolv_answer_item_pool, ar_item);
			item->ar_item = NULL;
		}

		/* Remove obsolete items */
		if (tick_is_lt(tick_add(item->last_seen, resolvers->hold.obsolete), now_ms)) {
			if (item->type == DNS_RTYPE_A || item->type == DNS_RTYPE_AAAA) {
				/* Remove any associated server */
				list_for_each_entry_safe(srv, srvback, &item->attached_servers, ip_rec_item) {
					LIST_DEL_INIT(&srv->ip_rec_item);
				}
			}
			else if (item->type == DNS_RTYPE_SRV) {
				/* Remove any associated server */
				list_for_each_entry_safe(srv, srvback, &item->attached_servers, srv_rec_item)
					resolv_srvrq_cleanup_srv(srv);
			}

			eb32_delete(&item->link);
			if (item->ar_item) {
				pool_free(resolv_answer_item_pool, item->ar_item);
				item->ar_item = NULL;
			}
			pool_free(resolv_answer_item_pool, item);
			continue;
		}

		if (item->type != DNS_RTYPE_SRV)
			continue;

		/* Now process SRV records */
		list_for_each_entry(req, &res->requesters, list) {
			struct ebpt_node *node;
			char target[DNS_MAX_NAME_SIZE+1];

			int i;
			if ((srvrq = objt_resolv_srvrq(req->owner)) == NULL)
				continue;

			/* Check if a server already uses that record */
			srv = NULL;
			list_for_each_entry(srv, &item->attached_servers, srv_rec_item) {
				if (srv->srvrq == srvrq) {
					HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
					goto srv_found;
				}
			}


			/* If not empty we try to match a server
			 * in server state file tree with the same hostname
			 */
			if (!eb_is_empty(&srvrq->named_servers)) {
				srv = NULL;

				/* convert the key to lookup in lower case */
				for (i = 0 ; item->data.target[i] ; i++)
					target[i] = tolower(item->data.target[i]);
				target[i] = 0;

				node = ebis_lookup(&srvrq->named_servers, target);
				if (node) {
					srv = ebpt_entry(node, struct server, host_dn);
					HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);

					/* an entry was found with the same hostname
					 * let check this node if the port matches
					 * and try next node if the hostname
					 * is still the same
					 */
					while (1) {
						if (srv->svc_port == item->port) {
							/* server found, we remove it from tree */
							ebpt_delete(node);
							ha_free(&srv->host_dn.key);
							goto srv_found;
						}

						HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);

						node = ebpt_next(node);
						if (!node)
							break;

						srv = ebpt_entry(node, struct server, host_dn);
						HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);

						if ((item->data_len != srv->hostname_dn_len)
						    || memcmp(srv->hostname_dn, item->data.target, item->data_len) != 0) {
							HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
							break;
						}
					}
				}
			}

			/* Pick the first server listed in srvrq (those ones don't
			 * have hostname and are free to use)
			 */
			srv = NULL;
			list_for_each_entry(srv, &srvrq->attached_servers, srv_rec_item) {
				LIST_DEL_INIT(&srv->srv_rec_item);
				HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
				goto srv_found;
			}
			srv = NULL;

srv_found:
			/* And update this server, if found (srv is locked here) */
			if (srv) {
				struct server_inetaddr srv_addr;
				uint8_t ip_change = 0;

				/* re-enable DNS resolution for this server by default */
				srv->flags &= ~SRV_F_NO_RESOLUTION;
				srv->srvrq_check->expire = TICK_ETERNITY;

				server_get_inetaddr(srv, &srv_addr);
				srv_addr.port.svc = item->port;
				srv_addr.port.map = 0;

				/* Check if an Additional Record is associated to this SRV record.
				 * Perform some sanity checks too to ensure the record can be used.
				 * If all fine, we simply pick up the IP address found and associate
				 * it to the server. And DNS resolution is disabled for this server.
				 */
				if ((item->ar_item != NULL) &&
				    (item->ar_item->type == DNS_RTYPE_A || item->ar_item->type == DNS_RTYPE_AAAA))
				{

					switch (item->ar_item->type) {
						case DNS_RTYPE_A:
							srv_addr.family = AF_INET;
							srv_addr.addr.v4 = item->ar_item->data.in4.sin_addr;
						break;
						case DNS_RTYPE_AAAA:
							srv_addr.family = AF_INET6;
							srv_addr.addr.v6 = item->ar_item->data.in6.sin6_addr;
						break;
					}

					srv->flags |= SRV_F_NO_RESOLUTION;

					/* Unlink A/AAAA resolution for this server if there is an AR item.
					 * It is usless to perform an extra resolution
					 */
					_resolv_unlink_resolution(srv->resolv_requester);

					ip_change = 1;
				}

				if (ip_change)
					server_set_inetaddr_warn(srv, &srv_addr, SERVER_INETADDR_UPDATER_DNS_AR);
				else
					server_set_inetaddr(srv, &srv_addr, SERVER_INETADDR_UPDATER_NONE, NULL);

				if (!srv->hostname_dn) {
					const char *msg = NULL;
					char hostname[DNS_MAX_NAME_SIZE+1];

					if (resolv_dn_label_to_str(item->data.target, item->data_len,
					                           hostname, sizeof(hostname)) == -1) {
						HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
						continue;
					}
					msg = srv_update_fqdn(srv, hostname, "SRV record", 1);
					if (msg)
						send_log(srv->proxy, LOG_NOTICE, "%s", msg);
				}

				if (!LIST_INLIST(&srv->srv_rec_item))
					LIST_APPEND(&item->attached_servers, &srv->srv_rec_item);

				if (!(srv->flags & SRV_F_NO_RESOLUTION)) {
					/* If there is no AR item responsible of the FQDN resolution,
					 * trigger a dedicated DNS resolution
					 */
					if (!srv->resolv_requester || !srv->resolv_requester->resolution)
						resolv_link_resolution(srv, OBJ_TYPE_SERVER, 1);
				}

				if (!srv->resolv_opts.ignore_weight) {
					char weight[9];
					int ha_weight;

					/* DNS weight range if from 0 to 65535
					 * HAProxy weight is from 0 to 256
					 * The rule below ensures that weight 0 is well respected
					 * while allowing a "mapping" from DNS weight into HAProxy's one.
					 */
					ha_weight = (item->weight + 255) / 256;

					snprintf(weight, sizeof(weight), "%d", ha_weight);
					server_parse_weight_change_request(srv, weight);
				}
				HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
			}
		}
	}
}

/* Validates that the buffer DNS response provided in <resp> and finishing
 * before <bufend> is valid from a DNS protocol point of view.
 *
 * The result is stored in <resolution>' response, buf_response,
 * response_query_records and response_answer_records members.
 *
 * This function returns one of the RSLV_RESP_* code to indicate the type of
 * error found.
 */
static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufend,
                                        struct resolv_resolution *resolution, int max_answer_records)
{
	unsigned char *reader;
	char *previous_dname, tmpname[DNS_MAX_NAME_SIZE];
	int len, flags, offset;
	int nb_saved_records;
	struct resolv_query_item *query;
	struct resolv_answer_item *answer_record, *tmp_record;
	struct resolv_response *r_res;
	struct eb32_node *eb32;
	uint32_t key = 0;
	int i, found = 0;
	int cause = RSLV_RESP_ERROR;

	reader         = resp;
	len            = 0;
	previous_dname = NULL;
	query      = NULL;
	answer_record = NULL;

	/* Initialization of response buffer and structure */
	r_res = &resolution->response;

	/* query id */
	if (reader + 2 >= bufend)
		goto invalid_resp;

	r_res->header.id = reader[0] * 256 + reader[1];
	reader += 2;

	/* Flags and rcode are stored over 2 bytes
	 * First byte contains:
	 *  - response flag (1 bit)
	 *  - opcode (4 bits)
	 *  - authoritative (1 bit)
	 *  - truncated (1 bit)
	 *  - recursion desired (1 bit)
	 */
	if (reader + 2 >= bufend)
		goto invalid_resp;

	flags = reader[0] * 256 + reader[1];

	if ((flags & DNS_FLAG_REPLYCODE) != DNS_RCODE_NO_ERROR) {
		if ((flags & DNS_FLAG_REPLYCODE) == DNS_RCODE_NX_DOMAIN) {
			cause = RSLV_RESP_NX_DOMAIN;
			goto return_error;
		}
		else if ((flags & DNS_FLAG_REPLYCODE) == DNS_RCODE_REFUSED) {
			cause = RSLV_RESP_REFUSED;
			goto return_error;
		}
		else {
			cause = RSLV_RESP_ERROR;
			goto return_error;
		}
	}

	/* Move forward 2 bytes for flags */
	reader += 2;

	/* 2 bytes for question count */
	if (reader + 2 >= bufend)
		goto invalid_resp;
	r_res->header.qdcount = reader[0] * 256 + reader[1];
	/* (for now) we send one query only, so we expect only one in the
	 * response too */
	if (r_res->header.qdcount != 1) {
		cause = RSLV_RESP_QUERY_COUNT_ERROR;
		goto return_error;
	}

	if (r_res->header.qdcount > DNS_MAX_QUERY_RECORDS)
		goto invalid_resp;
	reader += 2;

	/* 2 bytes for answer count */
	if (reader + 2 >= bufend)
		goto invalid_resp;
	r_res->header.ancount = reader[0] * 256 + reader[1];
	if (r_res->header.ancount == 0) {
		cause = RSLV_RESP_ANCOUNT_ZERO;
		goto return_error;
	}

	/* Check if too many records are announced */
	if (r_res->header.ancount > max_answer_records)
		goto invalid_resp;
	reader += 2;

	/* 2 bytes authority count */
	if (reader + 2 >= bufend)
		goto invalid_resp;
	r_res->header.nscount = reader[0] * 256 + reader[1];
	reader += 2;

	/* 2 bytes additional count */
	if (reader + 2 >= bufend)
		goto invalid_resp;
	r_res->header.arcount = reader[0] * 256 + reader[1];
	reader += 2;

	/* Parsing dns queries. For now there is only one query and it exists
	 * because (qdcount == 1).
	 */
	query = &resolution->response_query_records[0];

	/* Name is a NULL terminated string in our case, since we have
	 * one query per response and the first one can't be compressed
	 * (using the 0x0c format) */
	offset = 0;
	len = resolv_read_name(resp, bufend, reader, query->name, DNS_MAX_NAME_SIZE, &offset, 0);

	if (len == 0)
		goto invalid_resp;

	/* Now let's check the query's dname corresponds to the one we sent. */
	if (len != resolution->hostname_dn_len ||
	    memcmp(query->name, resolution->hostname_dn, resolution->hostname_dn_len) != 0) {
		cause = RSLV_RESP_WRONG_NAME;
		goto return_error;
	}

	reader += offset;
	previous_dname = query->name;

	/* move forward 2 bytes for question type */
	if (reader + 2 >= bufend)
		goto invalid_resp;
	query->type = reader[0] * 256 + reader[1];
	reader += 2;

	/* move forward 2 bytes for question class */
	if (reader + 2 >= bufend)
		goto invalid_resp;
	query->class = reader[0] * 256 + reader[1];
	reader += 2;

	/* TRUNCATED flag must be checked after we could read the query type
	 * because a TRUNCATED SRV query type response can still be exploited
	 */
	if (query->type != DNS_RTYPE_SRV && flags & DNS_FLAG_TRUNCATED) {
		cause = RSLV_RESP_TRUNCATED;
		goto return_error;
	}

	/* now parsing response records */
	nb_saved_records = 0;
	for (i = 0; i < r_res->header.ancount; i++) {
		if (reader >= bufend)
			goto invalid_resp;

		answer_record = pool_alloc(resolv_answer_item_pool);
		if (answer_record == NULL)
			goto invalid_resp;

		/* initialization */
		answer_record->ar_item = NULL;
		answer_record->last_seen = TICK_ETERNITY;
		LIST_INIT(&answer_record->attached_servers);
		answer_record->link.node.leaf_p = NULL;

		offset = 0;
		len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);

		if (len == 0)
			goto invalid_resp;

		/* Check if the current record dname is valid.  previous_dname
		 * points either to queried dname or last CNAME target */
		if (query->type != DNS_RTYPE_SRV && memcmp(previous_dname, tmpname, len) != 0) {
			if (i == 0) {
				/* First record, means a mismatch issue between
				 * queried dname and dname found in the first
				 * record */
				goto invalid_resp;
			}
			else {
				/* If not the first record, this means we have a
				 * CNAME resolution error.
				 */
				cause = RSLV_RESP_CNAME_ERROR;
				goto return_error;
			}

		}

		memcpy(answer_record->name, tmpname, len);
		answer_record->name[len] = 0;

		reader += offset;
		if (reader >= bufend)
			goto invalid_resp;

		/* 2 bytes for record type (A, AAAA, CNAME, etc...) */
		if (reader + 2 > bufend)
			goto invalid_resp;

		answer_record->type = reader[0] * 256 + reader[1];
		reader += 2;

		/* 2 bytes for class (2) */
		if (reader + 2 > bufend)
			goto invalid_resp;

		answer_record->class = reader[0] * 256 + reader[1];
		reader += 2;

		/* 4 bytes for ttl (4) */
		if (reader + 4 > bufend)
			goto invalid_resp;

		answer_record->ttl =   reader[0] * 16777216 + reader[1] * 65536
		                     + reader[2] * 256 + reader[3];
		reader += 4;

		/* Now reading data len */
		if (reader + 2 > bufend)
			goto invalid_resp;

		answer_record->data_len = reader[0] * 256 + reader[1];

		/* Move forward 2 bytes for data len */
		reader += 2;

		if (reader + answer_record->data_len > bufend)
			goto invalid_resp;

		/* Analyzing record content */
		switch (answer_record->type) {
			case DNS_RTYPE_A:
				/* ipv4 is stored on 4 bytes */
				if (answer_record->data_len != 4)
					goto invalid_resp;

				answer_record->data.in4.sin_family = AF_INET;
				memcpy(&answer_record->data.in4.sin_addr, reader, answer_record->data_len);
				key = XXH32(reader, answer_record->data_len, answer_record->type);
				break;

			case DNS_RTYPE_CNAME:
				/* Check if this is the last record and update the caller about the status:
				 * no IP could be found and last record was a CNAME. Could be triggered
				 * by a wrong query type
				 *
				 * + 1 because answer_record_id starts at 0
				 * while number of answers is an integer and
				 * starts at 1.
				 */
				if (i + 1 == r_res->header.ancount) {
					cause = RSLV_RESP_CNAME_ERROR;
					goto return_error;
				}

				offset = 0;
				len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
				if (len == 0)
					goto invalid_resp;

				memcpy(answer_record->data.target, tmpname, len);
				answer_record->data.target[len] = 0;
				key = XXH32(tmpname, len, answer_record->type);
				previous_dname = answer_record->data.target;
				break;


			case DNS_RTYPE_SRV:
				/* Answer must contain :
				 * - 2 bytes for the priority
				 * - 2 bytes for the weight
				 * - 2 bytes for the port
				 * - the target hostname
				 */
				if (answer_record->data_len <= 6)
					goto invalid_resp;

				answer_record->priority = read_n16(reader);
				reader += sizeof(uint16_t);
				answer_record->weight = read_n16(reader);
				reader += sizeof(uint16_t);
				answer_record->port = read_n16(reader);
				reader += sizeof(uint16_t);
				offset = 0;
				len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
				if (len == 0)
					goto invalid_resp;

				answer_record->data_len = len;
				memcpy(answer_record->data.target, tmpname, len);
				answer_record->data.target[len] = 0;
				key = XXH32(tmpname, len, answer_record->type);
				if (answer_record->ar_item != NULL) {
					pool_free(resolv_answer_item_pool, answer_record->ar_item);
					answer_record->ar_item = NULL;
				}
				break;

			case DNS_RTYPE_AAAA:
				/* ipv6 is stored on 16 bytes */
				if (answer_record->data_len != 16)
					goto invalid_resp;

				answer_record->data.in6.sin6_family = AF_INET6;
				memcpy(&answer_record->data.in6.sin6_addr, reader, answer_record->data_len);
				key = XXH32(reader, answer_record->data_len, answer_record->type);
				break;

		} /* switch (record type) */

		/* Increment the counter for number of records saved into our
		 * local response */
		nb_saved_records++;

		/* Move forward answer_record->data_len for analyzing next
		 * record in the response */
		reader += ((answer_record->type == DNS_RTYPE_SRV)
			   ? offset
			   : answer_record->data_len);

		/* Lookup to see if we already had this entry */
		found = 0;

		for (eb32 = eb32_lookup(&r_res->answer_tree, key); eb32 != NULL;  eb32 = eb32_next(eb32)) {
			tmp_record = eb32_entry(eb32, typeof(*tmp_record), link);
			if (tmp_record->type != answer_record->type)
				continue;

			switch(tmp_record->type) {
				case DNS_RTYPE_A:
					if (!memcmp(&answer_record->data.in4.sin_addr,
						    &tmp_record->data.in4.sin_addr,
						    sizeof(answer_record->data.in4.sin_addr)))
						found = 1;
					break;

				case DNS_RTYPE_AAAA:
					if (!memcmp(&answer_record->data.in6.sin6_addr,
						    &tmp_record->data.in6.sin6_addr,
						    sizeof(answer_record->data.in6.sin6_addr)))
						found = 1;
					break;

			case DNS_RTYPE_SRV:
                                if (answer_record->data_len == tmp_record->data_len &&
				    memcmp(answer_record->data.target, tmp_record->data.target, answer_record->data_len) == 0 &&
				    answer_record->port == tmp_record->port) {
					tmp_record->weight = answer_record->weight;
                                        found = 1;
				}
                                break;

			default:
				break;
			}

			if (found == 1)
				break;
		}

		if (found == 1) {
			tmp_record->last_seen = now_ms;
			pool_free(resolv_answer_item_pool, answer_record);
			answer_record = NULL;
		}
		else {
			answer_record->last_seen = now_ms;
			answer_record->ar_item = NULL;
			answer_record->link.key = key;
			eb32_insert(&r_res->answer_tree, &answer_record->link);
			answer_record = NULL;
		}
	} /* for i 0 to ancount */

	/* Save the number of records we really own */
	r_res->header.ancount = nb_saved_records;

	/* now parsing additional records for SRV queries only */
	if (query->type != DNS_RTYPE_SRV)
		goto skip_parsing_additional_records;

	/* if we find Authority records, just skip them */
	for (i = 0; i < r_res->header.nscount; i++) {
		offset = 0;
		len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE,
		                    &offset, 0);
		if (len == 0)
			continue;

		if (reader + offset + 10 >= bufend)
			goto invalid_resp;

		reader += offset;
		/* skip 2 bytes for class */
		reader += 2;
		/* skip 2 bytes for type */
		reader += 2;
		/* skip 4 bytes for ttl */
		reader += 4;
		/* read data len */
		len = reader[0] * 256 + reader[1];
		reader += 2;

		if (reader + len >= bufend)
			goto invalid_resp;

		reader += len;
	}

	nb_saved_records = 0;
	for (i = 0; i < r_res->header.arcount; i++) {
		if (reader >= bufend)
			goto invalid_resp;

		answer_record = pool_alloc(resolv_answer_item_pool);
		if (answer_record == NULL)
			goto invalid_resp;
		answer_record->last_seen = TICK_ETERNITY;
		LIST_INIT(&answer_record->attached_servers);

		offset = 0;
		len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);

		if (len == 0) {
			pool_free(resolv_answer_item_pool, answer_record);
			answer_record = NULL;
			continue;
		}

		memcpy(answer_record->name, tmpname, len);
		answer_record->name[len] = 0;

		reader += offset;
		if (reader >= bufend)
			goto invalid_resp;

		/* 2 bytes for record type (A, AAAA, CNAME, etc...) */
		if (reader + 2 > bufend)
			goto invalid_resp;

		answer_record->type = reader[0] * 256 + reader[1];
		reader += 2;

		/* 2 bytes for class (2) */
		if (reader + 2 > bufend)
			goto invalid_resp;

		answer_record->class = reader[0] * 256 + reader[1];
		reader += 2;

		/* 4 bytes for ttl (4) */
		if (reader + 4 > bufend)
			goto invalid_resp;

		answer_record->ttl =   reader[0] * 16777216 + reader[1] * 65536
		                     + reader[2] * 256 + reader[3];
		reader += 4;

		/* Now reading data len */
		if (reader + 2 > bufend)
			goto invalid_resp;

		answer_record->data_len = reader[0] * 256 + reader[1];

		/* Move forward 2 bytes for data len */
		reader += 2;

		if (reader + answer_record->data_len > bufend)
			goto invalid_resp;

		/* Analyzing record content */
		switch (answer_record->type) {
			case DNS_RTYPE_A:
				/* ipv4 is stored on 4 bytes */
				if (answer_record->data_len != 4)
					goto invalid_resp;

				answer_record->data.in4.sin_family = AF_INET;
				memcpy(&answer_record->data.in4.sin_addr, reader, answer_record->data_len);
				break;

			case DNS_RTYPE_AAAA:
				/* ipv6 is stored on 16 bytes */
				if (answer_record->data_len != 16)
					goto invalid_resp;

				answer_record->data.in6.sin6_family = AF_INET6;
				memcpy(&answer_record->data.in6.sin6_addr, reader, answer_record->data_len);
				break;

			default:
				pool_free(resolv_answer_item_pool, answer_record);
				answer_record = NULL;
				continue;

		} /* switch (record type) */

		/* Increment the counter for number of records saved into our
		 * local response */
		nb_saved_records++;

		/* Move forward answer_record->data_len for analyzing next
		 * record in the response */
		reader += answer_record->data_len;

		/* Lookup to see if we already had this entry */
		found = 0;

		for (eb32 = eb32_first(&r_res->answer_tree); eb32 != NULL;  eb32 = eb32_next(eb32)) {
			struct resolv_answer_item *ar_item;

			tmp_record = eb32_entry(eb32, typeof(*tmp_record), link);
			if (tmp_record->type != DNS_RTYPE_SRV || !tmp_record->ar_item)
				continue;

			ar_item = tmp_record->ar_item;
			if (ar_item->type != answer_record->type || ar_item->last_seen == now_ms ||
			    len != tmp_record->data_len ||
			    memcmp(answer_record->name, tmp_record->data.target, tmp_record->data_len) != 0)
				continue;

			switch(ar_item->type) {
				case DNS_RTYPE_A:
					if (!memcmp(&answer_record->data.in4.sin_addr,
						    &ar_item->data.in4.sin_addr,
						    sizeof(answer_record->data.in4.sin_addr)))
						found = 1;
					break;

				case DNS_RTYPE_AAAA:
					if (!memcmp(&answer_record->data.in6.sin6_addr,
						    &ar_item->data.in6.sin6_addr,
						    sizeof(answer_record->data.in6.sin6_addr)))
						found = 1;
					break;

				default:
					break;
			}

			if (found == 1)
				break;
		}

		if (found == 1) {
			tmp_record->ar_item->last_seen = now_ms;
			pool_free(resolv_answer_item_pool, answer_record);
			answer_record = NULL;
		}
		else {
			answer_record->last_seen = now_ms;
			answer_record->ar_item = NULL;

			// looking for the SRV record in the response list linked to this additional record
			for (eb32 = eb32_first(&r_res->answer_tree); eb32 != NULL;  eb32 = eb32_next(eb32)) {
				tmp_record = eb32_entry(eb32, typeof(*tmp_record), link);

				if (tmp_record->type == DNS_RTYPE_SRV &&
				    tmp_record->ar_item == NULL &&
				    memcmp(tmp_record->data.target, answer_record->name, tmp_record->data_len) == 0) {
					/* Always use the received additional record to refresh info */
					pool_free(resolv_answer_item_pool, tmp_record->ar_item);
					tmp_record->ar_item = answer_record;
					answer_record = NULL;
					break;
				}
			}
			if (answer_record) {
				pool_free(resolv_answer_item_pool, answer_record);
				answer_record = NULL;
			}
		}
	} /* for i 0 to arcount */

 skip_parsing_additional_records:

	/* Save the number of records we really own */
	r_res->header.arcount = nb_saved_records;
	resolv_check_response(resolution);
	return RSLV_RESP_VALID;

 invalid_resp:
	cause = RSLV_RESP_INVALID;

 return_error:
	pool_free(resolv_answer_item_pool, answer_record);
	return cause;
}

/* Searches dn_name resolution in resp.
 * If existing IP not found, return the first IP matching family_priority,
 * otherwise, first ip found
 * The following tasks are the responsibility of the caller:
 *   - <r_res> contains an error free DNS response
 * For both cases above, resolv_validate_dns_response is required
 * returns one of the RSLV_UPD_* code
 */
int resolv_get_ip_from_response(struct resolv_response *r_res,
                             struct resolv_options *resolv_opts, void *currentip,
                             short currentip_sin_family,
                             void **newip, short *newip_sin_family,
                             struct server *owner)
{
	struct resolv_answer_item *record, *found_record = NULL;
	struct eb32_node *eb32;
	int family_priority;
	int currentip_found;
	unsigned char *newip4, *newip6;
	int currentip_sel;
	int j;
	int score, max_score;
	int allowed_duplicated_ip;

	/* srv is linked to an alive ip record */
	if (owner && LIST_INLIST(&owner->ip_rec_item))
		return RSLV_UPD_NO;

	family_priority   = resolv_opts->family_prio;
	allowed_duplicated_ip = resolv_opts->accept_duplicate_ip;
	*newip = newip4   = newip6 = NULL;
	currentip_found   = 0;
	*newip_sin_family = AF_UNSPEC;
	max_score         = -1;

	/* Select an IP regarding configuration preference.
	 * Top priority is the preferred network ip version,
	 * second priority is the preferred network.
	 * the last priority is the currently used IP,
	 *
	 * For these three priorities, a score is calculated. The
	 * weight are:
	 *  8 - preferred ip version.
	 *  4 - preferred network.
	 *  2 - if the ip in the record is not affected to any other server in the same backend (duplication)
	 *  1 - current ip.
	 * The result with the biggest score is returned.
	 */

	for (eb32 = eb32_first(&r_res->answer_tree); eb32 != NULL;  eb32 = eb32_next(eb32)) {
		void *ip;
		unsigned char ip_type;

		record = eb32_entry(eb32, typeof(*record), link);
		if (record->type == DNS_RTYPE_A) {
			ip_type = AF_INET;
			ip = &record->data.in4.sin_addr;
		}
		else if (record->type == DNS_RTYPE_AAAA) {
			ip_type = AF_INET6;
			ip = &record->data.in6.sin6_addr;
		}
		else
			continue;
		score = 0;

		/* Check for preferred ip protocol. */
		if (ip_type == family_priority)
			score += 8;

		/* Check for preferred network. */
		for (j = 0; j < resolv_opts->pref_net_nb; j++) {

			/* Compare only the same addresses class. */
			if (resolv_opts->pref_net[j].family != ip_type)
				continue;

			if ((ip_type == AF_INET &&
			     in_net_ipv4(ip,
			                 &resolv_opts->pref_net[j].mask.in4,
			                 &resolv_opts->pref_net[j].addr.in4)) ||
			    (ip_type == AF_INET6 &&
			     in_net_ipv6(ip,
			                 &resolv_opts->pref_net[j].mask.in6,
			                 &resolv_opts->pref_net[j].addr.in6))) {
				score += 4;
				break;
			}
		}

		/* Check if the IP found in the record is already affected to a
		 * member of a group.  If not, the score should be incremented
		 * by 2. */
		if (owner) {
			struct server *srv;
			int already_used = 0;

			list_for_each_entry(srv, &record->attached_servers, ip_rec_item) {
				if (srv == owner)
					continue;
				if (srv->proxy == owner->proxy) {
					already_used = 1;
					break;
				}
			}
			if (already_used) {
				if (!allowed_duplicated_ip) {
					continue;
				}
			}
			else {
				score += 2;
			}
		} else {
			score += 2;
		}

		/* Check for current ip matching. */
		if (ip_type == currentip_sin_family &&
		    ((currentip_sin_family == AF_INET &&
		      !memcmp(ip, currentip, 4)) ||
		     (currentip_sin_family == AF_INET6 &&
		      !memcmp(ip, currentip, 16)))) {
			score++;
			currentip_sel = 1;
		}
		else
			currentip_sel = 0;

		/* Keep the address if the score is better than the previous
		 * score. The maximum score is 15, if this value is reached, we
		 * break the parsing. Implicitly, this score is reached the ip
		 * selected is the current ip. */
		if (score > max_score) {
			if (ip_type == AF_INET)
				newip4 = ip;
			else
				newip6 = ip;
			found_record = record;
			currentip_found = currentip_sel;
			if (score == 15) {
				/* this was not registered on the current record but it matches
				 * let's fix it (it may comes from state file */
				if (owner)
					LIST_APPEND(&found_record->attached_servers, &owner->ip_rec_item);
				return RSLV_UPD_NO;
			}
			max_score = score;
		}
	} /* list for each record entries */

	/* No IP found in the response */
	if (!newip4 && !newip6)
		return RSLV_UPD_NO_IP_FOUND;

	/* Case when the caller looks first for an IPv4 address */
	if (family_priority == AF_INET) {
		if (newip4) {
			*newip = newip4;
			*newip_sin_family = AF_INET;
		}
		else if (newip6) {
			*newip = newip6;
			*newip_sin_family = AF_INET6;
		}
	}
	/* Case when the caller looks first for an IPv6 address */
	else if (family_priority == AF_INET6) {
		if (newip6) {
			*newip = newip6;
			*newip_sin_family = AF_INET6;
		}
		else if (newip4) {
			*newip = newip4;
			*newip_sin_family = AF_INET;
		}
	}
	/* Case when the caller have no preference (we prefer IPv6) */
	else if (family_priority == AF_UNSPEC) {
		if (newip6) {
			*newip = newip6;
			*newip_sin_family = AF_INET6;
		}
		else if (newip4) {
			*newip = newip4;
			*newip_sin_family = AF_INET;
		}
	}

	/* the ip of this record was chosen for the server */
	if (owner && found_record) {
		LIST_DEL_INIT(&owner->ip_rec_item);
		LIST_APPEND(&found_record->attached_servers, &owner->ip_rec_item);
	}

	eb32 = eb32_first(&r_res->answer_tree);
	if (eb32) {
		/* Move the first record to the end of the list, for internal
		 * round robin.
		 */
		eb32_delete(eb32);
		eb32_insert(&r_res->answer_tree, eb32);
	}

	return (currentip_found ? RSLV_UPD_NO : RSLV_UPD_SRVIP_NOT_FOUND);
}

/* Turns a domain name label into a string: 3www7haproxy3org into www.haproxy.org
 *
 * <dn> contains the input label of <dn_len> bytes long and does not need to be
 * null-terminated. <str> must be allocated large enough to contain a full host
 * name plus the trailing zero, and the allocated size must be passed in
 * <str_len>.
 *
 * In case of error, -1 is returned, otherwise, the number of bytes copied in
 * <str> (including the terminating null byte).
 */
int resolv_dn_label_to_str(const char *dn, int dn_len, char *str, int str_len)
{
	char *ptr;
	int i, sz;

	if (str_len < dn_len)
		return -1;

	ptr = str;
	for (i = 0; i < dn_len; ++i) {
		sz = dn[i];
		if (i)
			*ptr++ = '.';
		/* copy the string at i+1 to lower case */
		for (; sz > 0; sz--)
			*(ptr++) = tolower(dn[++i]);
	}
	*ptr++ = '\0';
	return (ptr - str);
}

/* Turns a string into domain name label: www.haproxy.org into 3www7haproxy3org
 *
 * <str> contains the input string that is <str_len> bytes long (trailing zero
 * not needed). <dn> buffer must be allocated large enough to contain the
 * encoded string and a trailing zero, so it must be at least str_len+2, and
 * this allocated buffer size must be passed in <dn_len>.
 *
 * In case of error, -1 is returned, otherwise, the number of bytes copied in
 * <dn> (excluding the terminating null byte).
 */
int resolv_str_to_dn_label(const char *str, int str_len, char *dn, int dn_len)
{
	int i, offset;

	if (dn_len < str_len + 2)
		return -1;

	/* First byte of dn will be used to store the length of the first
	 * label */
	offset = 0;
	for (i = 0; i < str_len; ++i) {
		if (str[i] == '.') {
			/* 2 or more consecutive dots is invalid */
			if (i == offset)
				return -1;

			/* ignore trailing dot */
			if (i + 1 == str_len)
				break;

			dn[offset] = (i - offset);
			offset = i+1;
			continue;
		}
		dn[i+1] = tolower(str[i]);
	}
	dn[offset] = i - offset;
	dn[i+1] = '\0';
	return i+1;
}

/* Validates host name:
 *  - total size
 *  - each label size individually
 * returns:
 *  0 in case of error. If <err> is not NULL, an error message is stored there.
 *  1 when no error. <err> is left unaffected.
 */
int resolv_hostname_validation(const char *string, char **err)
{
	int i;

	if (strlen(string) > DNS_MAX_NAME_SIZE) {
		if (err)
			*err = DNS_TOO_LONG_FQDN;
		return 0;
	}

	while (*string) {
		i = 0;
		while (*string && *string != '.' && i < DNS_MAX_LABEL_SIZE) {
			if (!(*string == '-' || *string == '_' ||
			      (*string >= 'a' && *string <= 'z') ||
			      (*string >= 'A' && *string <= 'Z') ||
			      (*string >= '0' && *string <= '9'))) {
				if (err)
					*err = DNS_INVALID_CHARACTER;
				return 0;
			}
			i++;
			string++;
		}

		if (!(*string))
			break;

		if (*string != '.' && i >= DNS_MAX_LABEL_SIZE) {
			if (err)
				*err = DNS_LABEL_TOO_LONG;
			return 0;
		}

		string++;
	}
	return 1;
}

/* Picks up an available resolution from the different resolution list
 * associated to a resolvers section, in this order:
 *   1. check in resolutions.curr for the same hostname and query_type
 *   2. check in resolutions.wait for the same hostname and query_type
 *   3. Get a new resolution from resolution pool
 *
 * Returns an available resolution, NULL if none found.
 */
static struct resolv_resolution *resolv_pick_resolution(struct resolvers *resolvers,
							char **hostname_dn, int hostname_dn_len,
							int query_type)
{
	struct resolv_resolution *res;

	if (!*hostname_dn)
		goto from_pool;

	/* Search for same hostname and query type in resolutions.curr */
	list_for_each_entry(res, &resolvers->resolutions.curr, list) {
		if (!res->hostname_dn)
			continue;
		if ((query_type == res->prefered_query_type) &&
		    hostname_dn_len == res->hostname_dn_len  &&
		    memcmp(*hostname_dn, res->hostname_dn, hostname_dn_len) == 0)
			return res;
	}

	/* Search for same hostname and query type in resolutions.wait */
	list_for_each_entry(res, &resolvers->resolutions.wait, list) {
		if (!res->hostname_dn)
			continue;
		if ((query_type == res->prefered_query_type) &&
		    hostname_dn_len == res->hostname_dn_len  &&
		    memcmp(*hostname_dn, res->hostname_dn, hostname_dn_len) == 0)
			return res;
	}

  from_pool:
	/* No resolution could be found, so let's allocate a new one */
	res = pool_zalloc(resolv_resolution_pool);
	if (res) {
		res->resolvers  = resolvers;
		res->uuid       = resolution_uuid;
		res->status     = RSLV_STATUS_NONE;
		res->step       = RSLV_STEP_NONE;
		res->last_valid = now_ms;

		LIST_INIT(&res->requesters);
		res->response.answer_tree = EB_ROOT;

		res->prefered_query_type = query_type;
		res->query_type          = query_type;
		res->hostname_dn         = *hostname_dn;
		res->hostname_dn_len     = hostname_dn_len;

		++resolution_uuid;

		/* Move the resolution to the resolvers wait queue */
		LIST_APPEND(&resolvers->resolutions.wait, &res->list);
	}
	return res;
}

/* deletes and frees all answer_items from the resolution's answer_list */
static void resolv_purge_resolution_answer_records(struct resolv_resolution *resolution)
{
	struct eb32_node *eb32, *eb32_back;
	struct resolv_answer_item *item;

	for (eb32 = eb32_first(&resolution->response.answer_tree);
	     eb32 && (eb32_back = eb32_next(eb32), 1);
	     eb32 = eb32_back) {
		item = eb32_entry(eb32, typeof(*item), link);
		eb32_delete(&item->link);
		pool_free(resolv_answer_item_pool, item->ar_item);
		pool_free(resolv_answer_item_pool, item);
	}
}

/* Releases a resolution from its requester(s) and move it back to the pool */
static void resolv_free_resolution(struct resolv_resolution *resolution)
{
	struct resolv_requester *req, *reqback;

	/* clean up configuration */
	resolv_reset_resolution(resolution);
	resolution->hostname_dn = NULL;
	resolution->hostname_dn_len = 0;

	list_for_each_entry_safe(req, reqback, &resolution->requesters, list) {
		LIST_DEL_INIT(&req->list);
		req->resolution = NULL;
	}
	resolv_purge_resolution_answer_records(resolution);

	LIST_DEL_INIT(&resolution->list);
	pool_free(resolv_resolution_pool, resolution);
}

/* If *<req> is not NULL, returns it, otherwise tries to allocate a requester
 * and makes it owned by this obj_type, with the proposed callback and error
 * callback. On success, *req is assigned the allocated requester. Returns
 * NULL on allocation failure.
 */
static struct resolv_requester *
resolv_get_requester(struct resolv_requester **req, enum obj_type *owner,
                     int (*cb)(struct resolv_requester *, struct dns_counters *),
                     int (*err_cb)(struct resolv_requester *, int))
{
	struct resolv_requester *tmp;

	if (*req)
		return *req;

	tmp = pool_alloc(resolv_requester_pool);
	if (!tmp)
		goto end;

	LIST_INIT(&tmp->list);
	tmp->owner              = owner;
	tmp->resolution         = NULL;
	tmp->requester_cb       = cb;
	tmp->requester_error_cb = err_cb;
	*req = tmp;
 end:
	return tmp;
}

/* Links a requester (a server or a resolv_srvrq) with a resolution. It returns 0
 * on success, -1 otherwise.
 */
int resolv_link_resolution(void *requester, int requester_type, int requester_locked)
{
	struct resolv_resolution *res = NULL;
	struct resolv_requester  *req;
	struct resolvers  *resolvers;
	struct server         *srv   = NULL;
	struct resolv_srvrq      *srvrq = NULL;
	struct stream         *stream = NULL;
	char **hostname_dn;
	int   hostname_dn_len, query_type;

	enter_resolver_code();
	switch (requester_type) {
		case OBJ_TYPE_SERVER:
			srv             = (struct server *)requester;

			if (!requester_locked)
				HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);

			req = resolv_get_requester(&srv->resolv_requester,
			                           &srv->obj_type,
				                   snr_resolution_cb,
				                   snr_resolution_error_cb);

			if (!requester_locked)
				HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);

			if (!req)
				goto err;

			hostname_dn     = &srv->hostname_dn;
			hostname_dn_len = srv->hostname_dn_len;
			resolvers       = srv->resolvers;
			query_type      = ((srv->resolv_opts.family_prio == AF_INET)
					   ? DNS_RTYPE_A
					   : DNS_RTYPE_AAAA);
			break;

		case OBJ_TYPE_SRVRQ:
			srvrq           = (struct resolv_srvrq *)requester;

			req = resolv_get_requester(&srvrq->requester,
			                           &srvrq->obj_type,
			                           snr_resolution_cb,
			                           srvrq_resolution_error_cb);
			if (!req)
				goto err;

			hostname_dn     = &srvrq->hostname_dn;
			hostname_dn_len = srvrq->hostname_dn_len;
			resolvers       = srvrq->resolvers;
			query_type      = DNS_RTYPE_SRV;
			break;

		case OBJ_TYPE_STREAM:
			stream          = (struct stream *)requester;

			req = resolv_get_requester(&stream->resolv_ctx.requester,
			                           &stream->obj_type,
			                           act_resolution_cb,
			                           act_resolution_error_cb);
			if (!req)
				goto err;

			hostname_dn     = &stream->resolv_ctx.hostname_dn;
			hostname_dn_len = stream->resolv_ctx.hostname_dn_len;
			resolvers       = stream->resolv_ctx.parent->arg.resolv.resolvers;
			query_type      = ((stream->resolv_ctx.parent->arg.resolv.opts->family_prio == AF_INET)
					   ? DNS_RTYPE_A
					   : DNS_RTYPE_AAAA);
			break;
		default:
			goto err;
	}

	/* Get a resolution from the resolvers' wait queue or pool */
	if ((res = resolv_pick_resolution(resolvers, hostname_dn, hostname_dn_len, query_type)) == NULL)
		goto err;

	req->resolution = res;

	LIST_APPEND(&res->requesters, &req->list);
	leave_resolver_code();
	return 0;

  err:
	if (res && LIST_ISEMPTY(&res->requesters))
		resolv_free_resolution(res);
	leave_resolver_code();
	return -1;
}

/* This function removes all server/srvrq references on answer items. */
void resolv_detach_from_resolution_answer_items(struct resolv_resolution *res,  struct resolv_requester *req)
{
	struct eb32_node *eb32, *eb32_back;
	struct resolv_answer_item *item;
	struct server *srv, *srvback;
	struct resolv_srvrq    *srvrq;

	enter_resolver_code();
	if ((srv = objt_server(req->owner)) != NULL) {
		LIST_DEL_INIT(&srv->ip_rec_item);
	}
	else if ((srvrq = objt_resolv_srvrq(req->owner)) != NULL) {
		for (eb32 = eb32_first(&res->response.answer_tree);
		     eb32 && (eb32_back = eb32_next(eb32), 1);
		     eb32 = eb32_back) {
			item = eb32_entry(eb32, typeof(*item), link);
			if (item->type == DNS_RTYPE_SRV) {
				list_for_each_entry_safe(srv, srvback, &item->attached_servers, srv_rec_item) {
					if (srv->srvrq == srvrq)
						resolv_srvrq_cleanup_srv(srv);
				}
			}
		}
	}
	leave_resolver_code();
}

/* Removes a requester from a DNS resolution. It takes takes care of all the
 * consequences. It also cleans up some parameters from the requester.
 */
static void _resolv_unlink_resolution(struct resolv_requester *requester)
{
	struct resolv_resolution *res;
	struct resolv_requester  *req;

	/* Nothing to do */
	if (!requester || !requester->resolution)
		return;
	res = requester->resolution;

	/* Clean up the requester */
	LIST_DEL_INIT(&requester->list);
	requester->resolution = NULL;

	/* remove ref from the resolution answer item list to the requester */
	resolv_detach_from_resolution_answer_items(res,  requester);

	/* We need to find another requester linked on this resolution */
	if (!LIST_ISEMPTY(&res->requesters))
		req = LIST_NEXT(&res->requesters, struct resolv_requester *, list);
	else {
		abort_resolution(res);
		return;
	}

	/* Move hostname_dn related pointers to the next requester */
	switch (obj_type(req->owner)) {
		case OBJ_TYPE_SERVER:
			res->hostname_dn     = __objt_server(req->owner)->hostname_dn;
			res->hostname_dn_len = __objt_server(req->owner)->hostname_dn_len;
			break;
		case OBJ_TYPE_SRVRQ:
			res->hostname_dn     = __objt_resolv_srvrq(req->owner)->hostname_dn;
			res->hostname_dn_len = __objt_resolv_srvrq(req->owner)->hostname_dn_len;
			break;
		case OBJ_TYPE_STREAM:
			res->hostname_dn     = __objt_stream(req->owner)->resolv_ctx.hostname_dn;
			res->hostname_dn_len = __objt_stream(req->owner)->resolv_ctx.hostname_dn_len;
			break;
		default:
			res->hostname_dn     = NULL;
			res->hostname_dn_len = 0;
			break;
	}
}

/* The public version of the function above that deals with the death row. */
void resolv_unlink_resolution(struct resolv_requester *requester)
{
	enter_resolver_code();
	_resolv_unlink_resolution(requester);
	leave_resolver_code();
}

/* Called when a network IO is generated on a name server socket for an incoming
 * packet. It performs the following actions:
 *  - check if the packet requires processing (not outdated resolution)
 *  - ensure the DNS packet received is valid and call requester's callback
 *  - call requester's error callback if invalid response
 *  - check the dn_name in the packet against the one sent
 */
static int resolv_process_responses(struct dns_nameserver *ns)
{
	struct dns_counters   *tmpcounters;
	struct resolvers  *resolvers;
	struct resolv_resolution *res;
	unsigned char  buf[DNS_MAX_UDP_MESSAGE + 1];
	unsigned char *bufend;
	int buflen, dns_resp;
	int max_answer_records;
	unsigned short query_id;
	struct eb32_node *eb;
	struct resolv_requester *req;
	int keep_answer_items;

	resolvers = ns->parent;
	enter_resolver_code();
	HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);

	/* process all pending input messages */
	while (1) {
		/* read message received */
		memset(buf, '\0', resolvers->accepted_payload_size + 1);
		if ((buflen = dns_recv_nameserver(ns, (void *)buf, sizeof(buf))) <= 0) {
			break;
		}

		/* message too big */
		if (buflen > resolvers->accepted_payload_size) {
			ns->counters->app.resolver.too_big++;
			continue;
		}

		/* initializing variables */
		bufend = buf + buflen;	/* pointer to mark the end of the buffer */

		/* read the query id from the packet (16 bits) */
		if (buf + 2 > bufend) {
			ns->counters->app.resolver.invalid++;
			continue;
		}
		query_id = resolv_response_get_query_id(buf);

		/* search the query_id in the pending resolution tree */
		eb = eb32_lookup(&resolvers->query_ids, query_id);
		if (eb == NULL) {
			/* unknown query id means an outdated response and can be safely ignored */
			ns->counters->app.resolver.outdated++;
			continue;
		}

		/* known query id means a resolution in progress */
		res = eb32_entry(eb, struct resolv_resolution, qid);
		/* number of responses received */
		res->nb_responses++;

		max_answer_records = (resolvers->accepted_payload_size - DNS_HEADER_SIZE) / DNS_MIN_RECORD_SIZE;
		dns_resp = resolv_validate_dns_response(buf, bufend, res, max_answer_records);

		switch (dns_resp) {
			case RSLV_RESP_VALID:
				break;

			case RSLV_RESP_INVALID:
			case RSLV_RESP_QUERY_COUNT_ERROR:
			case RSLV_RESP_WRONG_NAME:
				res->status = RSLV_STATUS_INVALID;
				ns->counters->app.resolver.invalid++;
				break;

			case RSLV_RESP_NX_DOMAIN:
				res->status = RSLV_STATUS_NX;
				ns->counters->app.resolver.nx++;
				break;

			case RSLV_RESP_REFUSED:
				res->status = RSLV_STATUS_REFUSED;
				ns->counters->app.resolver.refused++;
				break;

			case RSLV_RESP_ANCOUNT_ZERO:
				res->status = RSLV_STATUS_OTHER;
				ns->counters->app.resolver.any_err++;
				break;

			case RSLV_RESP_CNAME_ERROR:
				res->status = RSLV_STATUS_OTHER;
				ns->counters->app.resolver.cname_error++;
				break;

			case RSLV_RESP_TRUNCATED:
				res->status = RSLV_STATUS_OTHER;
				ns->counters->app.resolver.truncated++;
				break;

			case RSLV_RESP_NO_EXPECTED_RECORD:
			case RSLV_RESP_ERROR:
			case RSLV_RESP_INTERNAL:
				res->status = RSLV_STATUS_OTHER;
				ns->counters->app.resolver.other++;
				break;
		}

		/* Wait all nameservers response to handle errors */
		if (dns_resp != RSLV_RESP_VALID && res->nb_responses < res->nb_queries)
			continue;

		/* Process error codes */
		if (dns_resp != RSLV_RESP_VALID)  {
			if (res->prefered_query_type != res->query_type) {
				/* The fallback on the query type was already performed,
				 * so check the try counter. If it falls to 0, we can
				 * report an error. Else, wait the next attempt. */
				if (!res->try)
					goto report_res_error;
			}
			else {
				/* Fallback from A to AAAA or the opposite and re-send
				 * the resolution immediately. try counter is not
				 * decremented. */
				if (res->prefered_query_type == DNS_RTYPE_A) {
					res->query_type = DNS_RTYPE_AAAA;
					resolv_send_query(res);
				}
				else if (res->prefered_query_type == DNS_RTYPE_AAAA) {
					res->query_type = DNS_RTYPE_A;
					resolv_send_query(res);
				}
			}
			continue;
		}

		/* So the resolution succeeded */
		res->status     = RSLV_STATUS_VALID;
		res->last_valid = now_ms;
		ns->counters->app.resolver.valid++;
		goto report_res_success;

	report_res_error:
		keep_answer_items = 0;
		list_for_each_entry(req, &res->requesters, list)
			keep_answer_items |= req->requester_error_cb(req, dns_resp);
		if (!keep_answer_items)
			resolv_purge_resolution_answer_records(res);
		resolv_reset_resolution(res);
		LIST_DEL_INIT(&res->list);
		LIST_APPEND(&resolvers->resolutions.wait, &res->list);
		continue;

	report_res_success:
		/* Only the 1rst requester s managed by the server, others are
		 * from the cache */
		tmpcounters = ns->counters;
		list_for_each_entry(req, &res->requesters, list) {
			struct server *s = objt_server(req->owner);

			if (s)
				HA_SPIN_LOCK(SERVER_LOCK, &s->lock);
			req->requester_cb(req, tmpcounters);
			if (s)
				HA_SPIN_UNLOCK(SERVER_LOCK, &s->lock);
			tmpcounters = NULL;
		}

		resolv_reset_resolution(res);
		LIST_DEL_INIT(&res->list);
		LIST_APPEND(&resolvers->resolutions.wait, &res->list);
		continue;
	}
	resolv_update_resolvers_timeout(resolvers);
	HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);
	leave_resolver_code();
	return buflen;
}

/* Processes DNS resolution. First, it checks the active list to detect expired
 * resolutions and retry them if possible. Else a timeout is reported. Then, it
 * checks the wait list to trigger new resolutions.
 */
struct task *process_resolvers(struct task *t, void *context, unsigned int state)
{
	struct resolvers  *resolvers = context;
	struct resolv_resolution *res, *resback;
	int exp;

	enter_resolver_code();
	HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);

	/* Handle all expired resolutions from the active list. Elements that
	 * need to be removed will in fact be moved to the death_row. Other
	 * ones will be handled normally.
	 */

	res  = LIST_NEXT(&resolvers->resolutions.curr, struct resolv_resolution *, list);
	while (&res->list != &resolvers->resolutions.curr) {
		resback = LIST_NEXT(&res->list, struct resolv_resolution *, list);

		if (LIST_ISEMPTY(&res->requesters)) {
			abort_resolution(res);
			res = resback;
			continue;
		}

		/* When we find the first resolution in the future, then we can
		 * stop here */
		exp = tick_add(res->last_query, resolvers->timeout.retry);
		if (!tick_is_expired(exp, now_ms))
			break;

		/* If current resolution has been tried too many times and
		 * finishes in timeout we update its status and remove it from
		 * the list */
		if (!res->try) {
			struct resolv_requester *req;
			int keep_answer_items = 0;

			/* Notify the result to the requesters */
			if (!res->nb_responses)
				res->status = RSLV_STATUS_TIMEOUT;
			list_for_each_entry(req, &res->requesters, list)
				keep_answer_items |= req->requester_error_cb(req, res->status);
			if (!keep_answer_items)
				resolv_purge_resolution_answer_records(res);

			/* Clean up resolution info and remove it from the
			 * current list */
			resolv_reset_resolution(res);

			/* subsequent entries might have been deleted here */
			resback = LIST_NEXT(&res->list, struct resolv_resolution *, list);
			LIST_DEL_INIT(&res->list);
			LIST_APPEND(&resolvers->resolutions.wait, &res->list);
			res = resback;
		}
		else {
			/* Otherwise resend the DNS query and requeue the resolution */
			if (!res->nb_responses || res->prefered_query_type != res->query_type) {
				/* No response received (a real timeout) or fallback already done */
				res->query_type = res->prefered_query_type;
				res->try--;
			}
			else {
				/* Fallback from A to AAAA or the opposite and re-send
				 * the resolution immediately. try counter is not
				 * decremented. */
				if (res->prefered_query_type == DNS_RTYPE_A)
					res->query_type = DNS_RTYPE_AAAA;
				else if (res->prefered_query_type == DNS_RTYPE_AAAA)
					res->query_type = DNS_RTYPE_A;
				else
					res->try--;
			}
			resolv_send_query(res);
			resback = LIST_NEXT(&res->list, struct resolv_resolution *, list);
			res = resback;
		}
	}

	/* Handle all resolutions in the wait list */
	list_for_each_entry_safe(res, resback, &resolvers->resolutions.wait, list) {

		if (unlikely(stopping)) {
			/* If haproxy is stopping, check if the resolution to know if it must be run or not.
			 * If at least a requester is a stream (because of a do-resolv action) or if there
			 * is a requester attached to a running proxy, the resolution is performed.
			 * Otherwise, it is skipped for now.
			 */
			struct resolv_requester *req;
			int must_run = 0;

			list_for_each_entry(req, &res->requesters, list) {
				struct proxy *px = NULL;

				switch (obj_type(req->owner)) {
					case OBJ_TYPE_SERVER:
						px = __objt_server(req->owner)->proxy;
						break;
					case OBJ_TYPE_SRVRQ:
						px = __objt_resolv_srvrq(req->owner)->proxy;
						break;
					case OBJ_TYPE_STREAM:
						/* Always perform the resolution */
						must_run = 1;
						break;
					default:
						break;
				}
				/* Perform the resolution if the proxy is not stopped or disabled */
				if (px && !(px->flags & (PR_FL_DISABLED|PR_FL_STOPPED)))
					must_run = 1;

				if (must_run)
					break;
			}

			if (!must_run) {
				/* Skip the reolsution. reset it and wait for the next wakeup */
				resolv_reset_resolution(res);
				continue;
			}
		}

		if (LIST_ISEMPTY(&res->requesters)) {
			abort_resolution(res);
			continue;
		}

		exp = tick_add(res->last_resolution, resolv_resolution_timeout(res));
		if (tick_isset(res->last_resolution) && !tick_is_expired(exp, now_ms))
			continue;

		if (resolv_run_resolution(res) != 1) {
			res->last_resolution = now_ms;
			LIST_DEL_INIT(&res->list);
			LIST_APPEND(&resolvers->resolutions.wait, &res->list);
		}
	}

	resolv_update_resolvers_timeout(resolvers);
	HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);

	if (unlikely(stopping)) {
		struct dns_nameserver *ns;

		if (LIST_ISEMPTY(&resolvers->resolutions.curr))
			t->expire = TICK_ETERNITY;

		list_for_each_entry(ns, &resolvers->nameservers, list) {
			if (ns->stream)
				task_wakeup(ns->stream->task_idle, TASK_WOKEN_MSG);
		}
	}

	/* now we can purge all queued deletions */
	leave_resolver_code();
	return t;
}


/* destroy a resolvers */
static void resolvers_destroy(struct resolvers *resolvers)
{
	struct dns_nameserver *ns, *nsback;
	struct resolv_resolution *res, *resback;
	struct resolv_requester  *req, *reqback;

	list_for_each_entry_safe(ns, nsback, &resolvers->nameservers, list) {
		free(ns->id);
		free((char *)ns->conf.file);
		if (ns->dgram) {
			if (ns->dgram->conn.t.sock.fd != -1) {
				fd_delete(ns->dgram->conn.t.sock.fd);
				close(ns->dgram->conn.t.sock.fd);
			}
			dns_ring_free(ns->dgram->ring_req);
			free(ns->dgram);
		}
		if (ns->stream) {
			dns_ring_free(ns->stream->ring_req);
			task_destroy(ns->stream->task_req);
			task_destroy(ns->stream->task_rsp);
			free(ns->stream);
		}
		LIST_DEL_INIT(&ns->list);
		EXTRA_COUNTERS_FREE(ns->extra_counters);
		free(ns);
	}

	list_for_each_entry_safe(res, resback, &resolvers->resolutions.curr, list) {
		list_for_each_entry_safe(req, reqback, &res->requesters, list) {
			LIST_DEL_INIT(&req->list);
			pool_free(resolv_requester_pool, req);
		}
		resolv_free_resolution(res);
	}

	list_for_each_entry_safe(res, resback, &resolvers->resolutions.wait, list) {
		list_for_each_entry_safe(req, reqback, &res->requesters, list) {
			LIST_DEL_INIT(&req->list);
			pool_free(resolv_requester_pool, req);
		}
		resolv_free_resolution(res);
	}

	free_proxy(resolvers->px);
	free(resolvers->id);
	free((char *)resolvers->conf.file);
	task_destroy(resolvers->t);
	LIST_DEL_INIT(&resolvers->list);
	free(resolvers);
}

/* Release memory allocated by DNS */
static void resolvers_deinit(void)
{
	struct resolvers  *resolvers, *resolversback;
	struct resolv_srvrq    *srvrq, *srvrqback;

	list_for_each_entry_safe(resolvers, resolversback, &sec_resolvers, list) {
		resolvers_destroy(resolvers);
	}

	list_for_each_entry_safe(srvrq, srvrqback, &resolv_srvrq_list, list) {
		free(srvrq->name);
		free(srvrq->hostname_dn);
		LIST_DEL_INIT(&srvrq->list);
		free(srvrq);
	}
}

/* Finalizes the DNS configuration by allocating required resources and checking
 * live parameters.
 * Returns 0 on success, 1 on error.
 */
static int resolvers_finalize_config(void)
{
	struct resolvers *resolvers;
	struct proxy	     *px;
	int err_code = 0;

	enter_resolver_code();

	/* allocate pool of resolution per resolvers */
	list_for_each_entry(resolvers, &sec_resolvers, list) {
		struct dns_nameserver *ns;
		struct task           *t;

		/* Check if we can create the socket with nameservers info */
		list_for_each_entry(ns, &resolvers->nameservers, list) {
			int fd;

			if (ns->dgram) {
				/* Check nameserver info */
				if ((fd = socket(ns->dgram->conn.addr.to.ss_family, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
					if (!resolvers->conf.implicit) {  /* emit a warning only if it was configured manually */
						ha_alert("resolvers '%s': can't create socket for nameserver '%s'.\n",
							 resolvers->id, ns->id);
						err_code |= (ERR_ALERT|ERR_ABORT);
					}
					continue;
				}
				if (connect(fd, (struct sockaddr*)&ns->dgram->conn.addr.to, get_addr_len(&ns->dgram->conn.addr.to)) == -1) {
					if (!resolvers->conf.implicit) { /* emit a warning only if it was configured manually */
						ha_warning("resolvers '%s': can't connect socket for nameserver '%s'.\n",
						            resolvers->id, ns->id);
					}
					close(fd);
					err_code |= ERR_WARN;
					continue;
				}
				close(fd);
			}
		}

		/* Create the task associated to the resolvers section */
		if ((t = task_new_anywhere()) == NULL) {
			ha_alert("resolvers '%s' : out of memory.\n", resolvers->id);
			err_code |= (ERR_ALERT|ERR_ABORT);
			goto err;
		}

		/* Update task's parameters */
		t->process   = process_resolvers;
		t->context   = resolvers;
		resolvers->t = t;
		task_wakeup(t, TASK_WOKEN_INIT);
	}

	for (px = proxies_list; px; px = px->next) {
		struct server *srv;

		if (px->flags & PR_FL_DISABLED) {
			/* must not run and will not work anyway since
			 * nothing in the proxy is initialized.
			 */
			continue;
		}

		for (srv = px->srv; srv; srv = srv->next) {
			struct resolvers *resolvers;

			if (!srv->resolvers_id)
				continue;

			if ((resolvers = find_resolvers_by_id(srv->resolvers_id)) == NULL) {
				ha_alert("%s '%s', server '%s': unable to find required resolvers '%s'\n",
					 proxy_type_str(px), px->id, srv->id, srv->resolvers_id);
				err_code |= (ERR_ALERT|ERR_ABORT);
				continue;
			}
			srv->resolvers = resolvers;
			srv->srvrq_check = NULL;
			if (srv->srvrq) {
				if (!srv->srvrq->resolvers) {
					srv->srvrq->resolvers = srv->resolvers;
					if (resolv_link_resolution(srv->srvrq, OBJ_TYPE_SRVRQ, 0) == -1) {
						ha_alert("%s '%s' : unable to set DNS resolution for server '%s'.\n",
							 proxy_type_str(px), px->id, srv->id);
						err_code |= (ERR_ALERT|ERR_ABORT);
						continue;
					}
				}

				srv->srvrq_check = task_new_anywhere();
				if (!srv->srvrq_check) {
					ha_alert("%s '%s' : unable to create SRVRQ task for server '%s'.\n",
						 proxy_type_str(px), px->id, srv->id);
					err_code |= (ERR_ALERT|ERR_ABORT);
					goto err;
				}
				srv->srvrq_check->process = resolv_srvrq_expire_task;
				srv->srvrq_check->context = srv;
				srv->srvrq_check->expire = TICK_ETERNITY;
			}
			else if (resolv_link_resolution(srv, OBJ_TYPE_SERVER, 0) == -1) {
				ha_alert("%s '%s', unable to set DNS resolution for server '%s'.\n",
					 proxy_type_str(px), px->id, srv->id);
				err_code |= (ERR_ALERT|ERR_ABORT);
				continue;
			}

			srv->flags |= SRV_F_NON_PURGEABLE;
		}
	}

	if (err_code & (ERR_ALERT|ERR_ABORT))
		goto err;

	leave_resolver_code();
	return 0;
  err:
	leave_resolver_code();
	resolvers_deinit();
	return 1;

}

static int stats_dump_resolv_to_buffer(struct stconn *sc,
                                    struct dns_nameserver *ns,
                                    struct field *stats, size_t stats_count,
                                    struct list *stat_modules)
{
	struct appctx *appctx = __sc_appctx(sc);
	struct stats_module *mod;
	size_t idx = 0;

	memset(stats, 0, sizeof(struct field) * stats_count);

	list_for_each_entry(mod, stat_modules, list) {
		struct counters_node *counters = EXTRA_COUNTERS_GET(ns->extra_counters, mod);

		if (!mod->fill_stats(counters, stats + idx, NULL))
			continue;
		idx += mod->stats_count;
	}

	if (!stats_dump_one_line(stats, idx, appctx))
		return 0;

	if (!stats_putchk(appctx, NULL, NULL))
		goto full;

	return 1;

  full:
	return 0;
}

/* Uses <appctx.ctx.stats.obj1> as a pointer to the current resolver and <obj2>
 * as a pointer to the current nameserver.
 */
int stats_dump_resolvers(struct stconn *sc,
                         struct field *stats, size_t stats_count,
                         struct list *stat_modules)
{
	struct appctx *appctx = __sc_appctx(sc);
	struct show_stat_ctx *ctx = appctx->svcctx;
	struct channel *rep = sc_ic(sc);
	struct resolvers *resolver = ctx->obj1;
	struct dns_nameserver *ns = ctx->obj2;

	if (!resolver)
		resolver = LIST_NEXT(&sec_resolvers, struct resolvers *, list);

	/* dump resolvers */
	list_for_each_entry_from(resolver, &sec_resolvers, list) {
		ctx->obj1 = resolver;

		ns = ctx->obj2 ?
		     ctx->obj2 :
		     LIST_NEXT(&resolver->nameservers, struct dns_nameserver *, list);

		list_for_each_entry_from(ns, &resolver->nameservers, list) {
			ctx->obj2 = ns;

			if (buffer_almost_full(&rep->buf)) {
				sc_need_room(sc, b_size(&rep->buf) / 2);
				goto full;
			}

			if (!stats_dump_resolv_to_buffer(sc, ns,
			                                 stats, stats_count,
			                                 stat_modules)) {
				return 0;
			}
		}

		ctx->obj2 = NULL;
	}

	return 1;

  full:
	return 0;
}

void resolv_stats_clear_counters(int clrall, struct list *stat_modules)
{
	struct resolvers  *resolvers;
	struct dns_nameserver *ns;
	struct stats_module *mod;
	void *counters;

	list_for_each_entry(mod, stat_modules, list) {
		if (!mod->clearable && !clrall)
			continue;

		list_for_each_entry(resolvers, &sec_resolvers, list) {
			list_for_each_entry(ns, &resolvers->nameservers, list) {
				counters = EXTRA_COUNTERS_GET(ns->extra_counters, mod);
				memcpy(counters, mod->counters, mod->counters_size);
			}
		}
	}

}

int resolv_allocate_counters(struct list *stat_modules)
{
	struct stats_module *mod;
	struct resolvers *resolvers;
	struct dns_nameserver *ns;

	list_for_each_entry(resolvers, &sec_resolvers, list) {
		list_for_each_entry(ns, &resolvers->nameservers, list) {
			EXTRA_COUNTERS_REGISTER(&ns->extra_counters, COUNTERS_RSLV,
			                        alloc_failed);

			list_for_each_entry(mod, stat_modules, list) {
				EXTRA_COUNTERS_ADD(mod,
				                   ns->extra_counters,
				                   mod->counters,
				                   mod->counters_size);
			}

			EXTRA_COUNTERS_ALLOC(ns->extra_counters, alloc_failed);

			list_for_each_entry(mod, stat_modules, list) {
				memcpy(ns->extra_counters->data + mod->counters_off[ns->extra_counters->type],
				       mod->counters, mod->counters_size);

				/* Store the ns counters pointer */
				if (strcmp(mod->name, "resolvers") == 0) {
					ns->counters = (struct dns_counters *)ns->extra_counters->data + mod->counters_off[COUNTERS_RSLV];
					ns->counters->id = ns->id;
					ns->counters->ns_puid = ns->puid;
					ns->counters->pid = resolvers->id;
				}
			}
		}
	}

	return 1;

alloc_failed:
	return 0;
}

/* if an arg is found, it sets the optional resolvers section pointer into a
 * show_resolvers_ctx struct pointed to by svcctx, or NULL when dumping all.
 */
static int cli_parse_stat_resolvers(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct show_resolvers_ctx *ctx = applet_reserve_svcctx(appctx, sizeof(*ctx));
	struct resolvers *presolvers;

	if (*args[2]) {
		list_for_each_entry(presolvers, &sec_resolvers, list) {
			if (strcmp(presolvers->id, args[2]) == 0) {
				ctx->forced_section = presolvers;
				break;
			}
		}
		if (ctx->forced_section == NULL)
			return cli_err(appctx, "Can't find that resolvers section\n");
	}
	return 0;
}

/* Dumps counters from all resolvers section and associated name servers. It
 * returns 0 if the output buffer is full and it needs to be called again,
 * otherwise non-zero. It may limit itself to the resolver pointed to by the
 * <resolvers> field of struct show_resolvers_ctx pointed to by <svcctx> if
 * it's not null.
 */
static int cli_io_handler_dump_resolvers_to_buffer(struct appctx *appctx)
{
	struct show_resolvers_ctx *ctx = appctx->svcctx;
	struct resolvers    *resolvers = ctx->resolvers;
	struct dns_nameserver   *ns;

	chunk_reset(&trash);

	if (LIST_ISEMPTY(&sec_resolvers)) {
		if (applet_putstr(appctx, "No resolvers found\n") == -1)
			goto full;
	}
	else {
		if (!resolvers)
			resolvers = LIST_ELEM(sec_resolvers.n, typeof(resolvers), list);

		list_for_each_entry_from(resolvers, &sec_resolvers, list) {
			if (ctx->forced_section != NULL && ctx->forced_section != resolvers)
				continue;

			ctx->resolvers = resolvers;
			ns = ctx->ns;

			if (!ns) {
				chunk_printf(&trash, "Resolvers section %s\n", resolvers->id);
				if (applet_putchk(appctx, &trash) == -1)
					goto full;

				ns = LIST_ELEM(resolvers->nameservers.n, typeof(ns), list);
				ctx->ns = ns;
			}

			list_for_each_entry_from(ns, &resolvers->nameservers, list) {
				chunk_reset(&trash);
				chunk_appendf(&trash, " nameserver %s:\n", ns->id);
				chunk_appendf(&trash, "  sent:        %lld\n", ns->counters->sent);
				chunk_appendf(&trash, "  snd_error:   %lld\n", ns->counters->snd_error);
				chunk_appendf(&trash, "  valid:       %lld\n", ns->counters->app.resolver.valid);
				chunk_appendf(&trash, "  update:      %lld\n", ns->counters->app.resolver.update);
				chunk_appendf(&trash, "  cname:       %lld\n", ns->counters->app.resolver.cname);
				chunk_appendf(&trash, "  cname_error: %lld\n", ns->counters->app.resolver.cname_error);
				chunk_appendf(&trash, "  any_err:     %lld\n", ns->counters->app.resolver.any_err);
				chunk_appendf(&trash, "  nx:          %lld\n", ns->counters->app.resolver.nx);
				chunk_appendf(&trash, "  timeout:     %lld\n", ns->counters->app.resolver.timeout);
				chunk_appendf(&trash, "  refused:     %lld\n", ns->counters->app.resolver.refused);
				chunk_appendf(&trash, "  other:       %lld\n", ns->counters->app.resolver.other);
				chunk_appendf(&trash, "  invalid:     %lld\n", ns->counters->app.resolver.invalid);
				chunk_appendf(&trash, "  too_big:     %lld\n", ns->counters->app.resolver.too_big);
				chunk_appendf(&trash, "  truncated:   %lld\n", ns->counters->app.resolver.truncated);
				chunk_appendf(&trash, "  outdated:    %lld\n",  ns->counters->app.resolver.outdated);
				if (applet_putchk(appctx, &trash) == -1)
					goto full;
				ctx->ns = ns;
			}

			ctx->ns = NULL;

			/* was this the only section to dump ? */
			if (ctx->forced_section)
				break;
		}
	}

	/* done! */
	return 1;
 full:
	/* the output buffer is full, retry later */
	return 0;
}

/* register cli keywords */
static struct cli_kw_list cli_kws = {{ }, {
		{ { "show", "resolvers", NULL }, "show resolvers [id]                     : dumps counters from all resolvers section and associated name servers",
		  cli_parse_stat_resolvers, cli_io_handler_dump_resolvers_to_buffer },
		{{},}
	}
};

INITCALL1(STG_REGISTER, cli_register_kw, &cli_kws);

/*
 * Prepare <rule> for hostname resolution.
 * Returns -1 in case of any allocation failure, 0 if not.
 * On error, a global failure counter is also incremented.
 */
static int action_prepare_for_resolution(struct stream *stream, const char *hostname, int hostname_len)
{
	char *hostname_dn;
	int   hostname_dn_len;
	struct buffer *tmp = get_trash_chunk();

	if (!hostname)
		return 0;

	hostname_dn     = tmp->area;
	hostname_dn_len = resolv_str_to_dn_label(hostname, hostname_len,
	                                         hostname_dn, tmp->size);
	if (hostname_dn_len == -1)
		goto err;


	stream->resolv_ctx.hostname_dn     = strdup(hostname_dn);
	stream->resolv_ctx.hostname_dn_len = hostname_dn_len;
	if (!stream->resolv_ctx.hostname_dn)
		goto err;

	return 0;

 err:
	ha_free(&stream->resolv_ctx.hostname_dn);
	resolv_failed_resolutions += 1;
	return -1;
}


/*
 * Execute the "do-resolution" action. May be called from {tcp,http}request.
 */
enum act_return resolv_action_do_resolve(struct act_rule *rule, struct proxy *px,
					      struct session *sess, struct stream *s, int flags)
{
	struct resolv_resolution *resolution;
	struct sample *smp;
	struct resolv_requester *req;
	struct resolvers  *resolvers;
	struct resolv_resolution *res;
	int exp, locked = 0;
	enum act_return ret = ACT_RET_CONT;

	resolvers = rule->arg.resolv.resolvers;

	enter_resolver_code();

	/* we have a response to our DNS resolution */
 use_cache:
	if (s->resolv_ctx.requester && s->resolv_ctx.requester->resolution != NULL) {
		resolution = s->resolv_ctx.requester->resolution;
		if (!locked) {
			HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);
			locked = 1;
		}

		if (resolution->step == RSLV_STEP_RUNNING)
			goto yield;
		if (resolution->step == RSLV_STEP_NONE) {
			/* We update the variable only if we have a valid
			 * response. If the response was not received yet, we
			 * must yield.
			 */
			if (resolution->status == RSLV_STATUS_NONE)
				goto yield;
			if (resolution->status == RSLV_STATUS_VALID) {
				struct sample smp;
				short ip_sin_family = 0;
				void *ip = NULL;

				resolv_get_ip_from_response(&resolution->response, rule->arg.resolv.opts, NULL,
							 0, &ip, &ip_sin_family, NULL);

				switch (ip_sin_family) {
				case AF_INET:
					smp.data.type = SMP_T_IPV4;
					memcpy(&smp.data.u.ipv4, ip, 4);
					break;
				case AF_INET6:
					smp.data.type = SMP_T_IPV6;
					memcpy(&smp.data.u.ipv6, ip, 16);
					break;
				default:
					ip = NULL;
				}

				if (ip) {
					smp.px = px;
					smp.sess = sess;
					smp.strm = s;

					vars_set_by_name(rule->arg.resolv.varname, strlen(rule->arg.resolv.varname), &smp);
				}
			}
		}

		goto release_requester;
	}

	/* need to configure and start a new DNS resolution */
	smp = sample_fetch_as_type(px, sess, s, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->arg.resolv.expr, SMP_T_STR);
	if (smp == NULL)
		goto end;

	if (action_prepare_for_resolution(s, smp->data.u.str.area, smp->data.u.str.data) == -1)
		goto end; /* on error, ignore the action */

	s->resolv_ctx.parent = rule;

	HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);
	locked = 1;

	resolv_link_resolution(s, OBJ_TYPE_STREAM, 0);

	/* Check if there is a fresh enough response in the cache of our associated resolution */
	req = s->resolv_ctx.requester;
	if (!req || !req->resolution)
		goto release_requester; /* on error, ignore the action */
	res = req->resolution;

	exp = tick_add(res->last_resolution, resolvers->hold.valid);
	if (resolvers->t && res->status == RSLV_STATUS_VALID && tick_isset(res->last_resolution)
	    && !tick_is_expired(exp, now_ms)) {
		goto use_cache;
	}

	resolv_trigger_resolution(s->resolv_ctx.requester);

  yield:
	if (flags & ACT_OPT_FINAL)
		goto release_requester;
	ret = ACT_RET_YIELD;

  end:
	leave_resolver_code();
	if (locked)
		HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);
	return ret;

  release_requester:
	ha_free(&s->resolv_ctx.hostname_dn);
	s->resolv_ctx.hostname_dn_len = 0;
	if (s->resolv_ctx.requester) {
		_resolv_unlink_resolution(s->resolv_ctx.requester);
		pool_free(resolv_requester_pool, s->resolv_ctx.requester);
		s->resolv_ctx.requester = NULL;
	}
	goto end;
}

static void release_resolv_action(struct act_rule *rule)
{
	release_sample_expr(rule->arg.resolv.expr);
	free(rule->arg.resolv.varname);
	free(rule->arg.resolv.resolvers_id);
	free(rule->arg.resolv.opts);
}


/* parse "do-resolve" action
 * This action takes the following arguments:
 *   do-resolve(<varName>,<resolversSectionName>,<resolvePrefer>) <expr>
 *
 *   - <varName> is the variable name where the result of the DNS resolution will be stored
 *     (mandatory)
 *   - <resolversSectionName> is the name of the resolvers section to use to perform the resolution
 *     (mandatory)
 *   - <resolvePrefer> can be either 'ipv4' or 'ipv6' and is the IP family we would like to resolve first
 *     (optional), defaults to ipv6
 *   - <expr> is an HAProxy expression used to fetch the name to be resolved
 */
enum act_parse_ret resolv_parse_do_resolve(const char **args, int *orig_arg, struct proxy *px, struct act_rule *rule, char **err)
{
	int cur_arg;
	struct sample_expr *expr;
	unsigned int where;
	const char *beg, *end;

	/* orig_arg points to the first argument, but we need to analyse the command itself first */
	cur_arg = *orig_arg - 1;

	/* locate varName, which is mandatory */
	beg = strchr(args[cur_arg], '(');
	if (beg == NULL)
		goto do_resolve_parse_error;
	beg = beg + 1; /* beg should points to the first character after opening parenthesis '(' */
	end = strchr(beg, ',');
	if (end == NULL)
		goto do_resolve_parse_error;
	rule->arg.resolv.varname = my_strndup(beg, end - beg);
	if (rule->arg.resolv.varname == NULL)
		goto do_resolve_parse_error;


	/* locate resolversSectionName, which is mandatory.
	 * Since next parameters are optional, the delimiter may be comma ','
	 * or closing parenthesis ')'
	 */
	beg = end + 1;
	end = strchr(beg, ',');
	if (end == NULL)
		end = strchr(beg, ')');
	if (end == NULL)
		goto do_resolve_parse_error;
	rule->arg.resolv.resolvers_id = my_strndup(beg, end - beg);
	if (rule->arg.resolv.resolvers_id == NULL)
		goto do_resolve_parse_error;


	rule->arg.resolv.opts = calloc(1, sizeof(*rule->arg.resolv.opts));
	if (rule->arg.resolv.opts == NULL)
		goto do_resolve_parse_error;

	/* Default priority is ipv6 */
	rule->arg.resolv.opts->family_prio = AF_INET6;

	/* optional arguments accepted for now:
	 *  ipv4 or ipv6
	 */
	while (*end != ')') {
		beg = end + 1;
		end = strchr(beg, ',');
		if (end == NULL)
			end = strchr(beg, ')');
		if (end == NULL)
			goto do_resolve_parse_error;

		if (strncmp(beg, "ipv4", end - beg) == 0) {
			rule->arg.resolv.opts->family_prio = AF_INET;
		}
		else if (strncmp(beg, "ipv6", end - beg) == 0) {
			rule->arg.resolv.opts->family_prio = AF_INET6;
		}
		else {
			goto do_resolve_parse_error;
		}
	}

	cur_arg = cur_arg + 1;

	expr = sample_parse_expr((char **)args, &cur_arg, px->conf.args.file, px->conf.args.line, err, &px->conf.args, NULL);
	if (!expr)
		goto do_resolve_parse_error;


	where = 0;
	if (px->cap & PR_CAP_FE)
		where |= SMP_VAL_FE_HRQ_HDR;
	if (px->cap & PR_CAP_BE)
		where |= SMP_VAL_BE_HRQ_HDR;

	if (!(expr->fetch->val & where)) {
		memprintf(err,
			  "fetch method '%s' extracts information from '%s', none of which is available here",
			  args[cur_arg-1], sample_src_names(expr->fetch->use));
		free(expr);
		return ACT_RET_PRS_ERR;
	}
	rule->arg.resolv.expr = expr;
	rule->action = ACT_CUSTOM;
	rule->action_ptr = resolv_action_do_resolve;
	*orig_arg = cur_arg;

	rule->check_ptr = check_action_do_resolve;
	rule->release_ptr = release_resolv_action;

	return ACT_RET_PRS_OK;

 do_resolve_parse_error:
	ha_free(&rule->arg.resolv.varname);
	ha_free(&rule->arg.resolv.resolvers_id);
	memprintf(err, "Can't parse '%s'. Expects 'do-resolve(<varname>,<resolvers>[,<options>]) <expr>'. Available options are 'ipv4' and 'ipv6'",
			args[cur_arg]);
	return ACT_RET_PRS_ERR;
}

static struct action_kw_list http_req_kws = { { }, {
	{ "do-resolve", resolv_parse_do_resolve, KWF_MATCH_PREFIX },
	{ /* END */ }
}};

INITCALL1(STG_REGISTER, http_req_keywords_register, &http_req_kws);

static struct action_kw_list tcp_req_cont_actions = {ILH, {
	{ "do-resolve", resolv_parse_do_resolve, KWF_MATCH_PREFIX },
	{ /* END */ }
}};

INITCALL1(STG_REGISTER, tcp_req_cont_keywords_register, &tcp_req_cont_actions);

/* Check an "http-request do-resolve" action.
 *
 * The function returns 1 in success case, otherwise, it returns 0 and err is
 * filled.
 */
int check_action_do_resolve(struct act_rule *rule, struct proxy *px, char **err)
{
	struct resolvers *resolvers = NULL;

	if (rule->arg.resolv.resolvers_id == NULL) {
		memprintf(err,"Proxy '%s': %s", px->id, "do-resolve action without resolvers");
		return 0;
	}

	resolvers = find_resolvers_by_id(rule->arg.resolv.resolvers_id);
	if (resolvers == NULL) {
		memprintf(err,"Can't find resolvers section '%s' for do-resolve action", rule->arg.resolv.resolvers_id);
		return 0;
	}
	rule->arg.resolv.resolvers = resolvers;

	return 1;
}

void resolvers_setup_proxy(struct proxy *px)
{
	px->fe_counters.last_change = px->be_counters.last_change = ns_to_sec(now_ns);
	px->cap = PR_CAP_FE | PR_CAP_BE;
	px->maxconn = 0;
	px->conn_retries = 1;
	px->timeout.server = TICK_ETERNITY;
	px->timeout.client = TICK_ETERNITY;
	px->timeout.connect = 1000; // by default same than timeout.resolve
	px->accept = NULL;
	px->options2 |= PR_O2_INDEPSTR | PR_O2_SMARTCON;
}

static int parse_resolve_conf(char **errmsg, char **warnmsg)
{
	struct dns_nameserver *newnameserver = NULL;
	const char *whitespace = "\r\n\t ";
	char *resolv_line = NULL;
	int resolv_linenum = 0;
	FILE *f = NULL;
	char *address = NULL;
	struct sockaddr_storage *sk = NULL;
	struct protocol *proto;
	int duplicate_name = 0;
	int err_code = 0;

	if ((resolv_line = malloc(sizeof(*resolv_line) * LINESIZE)) == NULL) {
		memprintf(errmsg, "out of memory.\n");
		err_code |= ERR_ALERT | ERR_FATAL;
		goto resolv_out;
	}

	if ((f = fopen("/etc/resolv.conf", "r")) == NULL) {
		if (errmsg)
			memprintf(errmsg, "failed to open /etc/resolv.conf.");
		err_code |= ERR_ALERT | ERR_FATAL;
		goto resolv_out;
	}

	sk = calloc(1, sizeof(*sk));
	if (sk == NULL) {
		if (errmsg)
			memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
		err_code |= ERR_ALERT | ERR_FATAL;
		goto resolv_out;
	}

	while (fgets(resolv_line, LINESIZE, f) != NULL) {
		resolv_linenum++;
		if (strncmp(resolv_line, "nameserver", 10) != 0)
			continue;

		address = strtok(resolv_line + 10, whitespace);
		if (address == resolv_line + 10)
			continue;

		if (address == NULL) {
			if (warnmsg)
				memprintf(warnmsg, "%sparsing [/etc/resolv.conf:%d] : nameserver line is missing address.\n",
				          *warnmsg ? *warnmsg : "", resolv_linenum);
			err_code |= ERR_WARN;
			continue;
		}

		duplicate_name = 0;
		list_for_each_entry(newnameserver, &curr_resolvers->nameservers, list) {
			if (strcmp(newnameserver->id, address) == 0) {
				if (warnmsg)
					memprintf(warnmsg, "%sParsing [/etc/resolv.conf:%d] : generated name for /etc/resolv.conf nameserver '%s' conflicts with another nameserver (declared at %s:%d), it appears to be a duplicate and will be excluded.\n",
						  *warnmsg ? *warnmsg : "", resolv_linenum, address, newnameserver->conf.file, newnameserver->conf.line);
				err_code |= ERR_WARN;
				duplicate_name = 1;
			}
		}

		if (duplicate_name)
			continue;

		memset(sk, 0, sizeof(*sk));
		if (!str2ip2(address, sk, 1)) {
			if (warnmsg)
				memprintf(warnmsg, "%sparsing [/etc/resolv.conf:%d] : address '%s' could not be recognized, nameserver will be excluded.\n",
				          *warnmsg ? *warnmsg : "", resolv_linenum, address);
			err_code |= ERR_WARN;
			continue;
		}

		set_host_port(sk, 53);

		proto = protocol_lookup(sk->ss_family, PROTO_TYPE_STREAM, 0);
		if (!proto || !proto->connect) {
			if (warnmsg)
				memprintf(warnmsg, "%sparsing [/etc/resolv.conf:%d] : '%s' : connect() not supported for this address family.\n",
				          *warnmsg ? *warnmsg : "", resolv_linenum, address);
			err_code |= ERR_WARN;
			continue;
		}

		if ((newnameserver = calloc(1, sizeof(*newnameserver))) == NULL) {
			if (errmsg)
				memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto resolv_out;
		}

		if (dns_dgram_init(newnameserver, sk) < 0) {
			if (errmsg)
				memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
			err_code |= ERR_ALERT | ERR_FATAL;
			free(newnameserver);
			goto resolv_out;
		}

		newnameserver->conf.file = strdup("/etc/resolv.conf");
		if (newnameserver->conf.file == NULL) {
			if (errmsg)
				memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
			err_code |= ERR_ALERT | ERR_FATAL;
			free(newnameserver);
			goto resolv_out;
		}

		newnameserver->id = strdup(address);
		if (newnameserver->id == NULL) {
			if (errmsg)
				memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
			err_code |= ERR_ALERT | ERR_FATAL;
			free((char *)newnameserver->conf.file);
			free(newnameserver);
			goto resolv_out;
		}

		newnameserver->parent = curr_resolvers;
		newnameserver->process_responses = resolv_process_responses;
		newnameserver->conf.line = resolv_linenum;
		newnameserver->puid = curr_resolvers->nb_nameservers;
		LIST_APPEND(&curr_resolvers->nameservers, &newnameserver->list);
		curr_resolvers->nb_nameservers++;
	}

resolv_out:
	free(sk);
	free(resolv_line);
	if (f != NULL)
		fclose(f);

	return err_code;
}

static int resolvers_new(struct resolvers **resolvers, const char *id, const char *file, int linenum)
{
	struct resolvers *r = NULL;
	struct proxy *p = NULL;
	int err_code = 0;

	if ((r = calloc(1, sizeof(*r))) == NULL) {
		err_code |= ERR_ALERT | ERR_ABORT;
		goto out;
	}

	/* allocate new proxy to tcp servers */
	p = calloc(1, sizeof *p);
	if (!p) {
		err_code |= ERR_ALERT | ERR_FATAL;
		goto out;
	}

	init_new_proxy(p);
	resolvers_setup_proxy(p);
	p->parent = r;
	p->id = strdup(id);
	p->conf.args.file = p->conf.file = strdup(file);
	p->conf.args.line = p->conf.line = linenum;
	r->px = p;

	/* default values */
	LIST_APPEND(&sec_resolvers, &r->list);
	r->conf.file = strdup(file);
	r->conf.line = linenum;
	r->id = strdup(id);
	r->query_ids = EB_ROOT;
	/* default maximum response size */
	r->accepted_payload_size = 512;
	/* default hold period for nx, other, refuse and timeout is 30s */
	r->hold.nx = 30000;
	r->hold.other = 30000;
	r->hold.refused = 30000;
	r->hold.timeout = 30000;
	r->hold.obsolete = 0;
	/* default hold period for valid is 10s */
	r->hold.valid = 10000;
	r->timeout.resolve = 1000;
	r->timeout.retry   = 1000;
	r->resolve_retries = 3;
	r->nb_nameservers = 0;
	LIST_INIT(&r->nameservers);
	LIST_INIT(&r->resolutions.curr);
	LIST_INIT(&r->resolutions.wait);
	HA_SPIN_INIT(&r->lock);

	*resolvers = r;

out:
	if (err_code & (ERR_FATAL|ERR_ABORT)) {
		ha_free(&r);
		ha_free(&p);
	}

	return err_code;
}


/*
 * Parse a <resolvers> section.
 * Returns the error code, 0 if OK, or any combination of :
 *  - ERR_ABORT: must abort ASAP
 *  - ERR_FATAL: we can continue parsing but not start the service
 *  - ERR_WARN: a warning has been emitted
 *  - ERR_ALERT: an alert has been emitted
 * Only the two first ones can stop processing, the two others are just
 * indicators.
 */
int cfg_parse_resolvers(const char *file, int linenum, char **args, int kwm)
{
	const char *err;
	int err_code = 0;
	char *errmsg = NULL;
	char *warnmsg = NULL;

	if (strcmp(args[0], "resolvers") == 0) { /* new resolvers section */
		if (!*args[1]) {
			ha_alert("parsing [%s:%d] : missing name for resolvers section.\n", file, linenum);
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}

		err = invalid_char(args[1]);
		if (err) {
			ha_alert("parsing [%s:%d] : character '%c' is not permitted in '%s' name '%s'.\n",
				 file, linenum, *err, args[0], args[1]);
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}

		list_for_each_entry(curr_resolvers, &sec_resolvers, list) {
			/* Error if two resolvers owns the same name */
			if (strcmp(curr_resolvers->id, args[1]) == 0) {
				ha_alert("Parsing [%s:%d]: resolvers '%s' has same name as another resolvers (declared at %s:%d).\n",
					 file, linenum, args[1], curr_resolvers->conf.file, curr_resolvers->conf.line);
				err_code |= ERR_ALERT | ERR_ABORT;
			}
		}

		err_code |= resolvers_new(&curr_resolvers, args[1], file, linenum);
		if (err_code & ERR_ALERT) {
			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
			goto out;
		}

	}
	else if (strcmp(args[0], "nameserver") == 0) { /* nameserver definition */
		struct dns_nameserver *newnameserver = NULL;
		struct sockaddr_storage *sk;
		int port1, port2;
		struct protocol *proto;

		if (!*args[2]) {
			ha_alert("parsing [%s:%d] : '%s' expects <name> and <addr>[:<port>] as arguments.\n",
				 file, linenum, args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		err = invalid_char(args[1]);
		if (err) {
			ha_alert("parsing [%s:%d] : character '%c' is not permitted in server name '%s'.\n",
				 file, linenum, *err, args[1]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		list_for_each_entry(newnameserver, &curr_resolvers->nameservers, list) {
			/* Error if two resolvers owns the same name */
			if (strcmp(newnameserver->id, args[1]) == 0) {
				ha_alert("Parsing [%s:%d]: nameserver '%s' has same name as another nameserver (declared at %s:%d).\n",
					 file, linenum, args[1], newnameserver->conf.file, newnameserver->conf.line);
				err_code |= ERR_ALERT | ERR_FATAL;
			}
		}

		sk = str2sa_range(args[2], NULL, &port1, &port2, NULL, &proto, NULL,
		                  &errmsg, NULL, NULL, PA_O_RESOLVE | PA_O_PORT_OK | PA_O_PORT_MAND | PA_O_DGRAM | PA_O_STREAM | PA_O_DEFAULT_DGRAM);
		if (!sk) {
			ha_alert("parsing [%s:%d] : '%s %s' : %s\n", file, linenum, args[0], args[1], errmsg);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		if ((newnameserver = calloc(1, sizeof(*newnameserver))) == NULL) {
			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}

		if (proto && proto->xprt_type == PROTO_TYPE_STREAM) {
			err_code |= parse_server(file, linenum, args, curr_resolvers->px, NULL,
			                         SRV_PARSE_PARSE_ADDR|SRV_PARSE_INITIAL_RESOLVE);
			if (err_code & (ERR_FATAL|ERR_ABORT)) {
				err_code |= ERR_ABORT;
				goto out;
			}

			if (dns_stream_init(newnameserver, curr_resolvers->px->srv) < 0) {
				ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
				err_code |= ERR_ALERT|ERR_ABORT;
				goto out;
			}
		}
		else if (dns_dgram_init(newnameserver, sk) < 0) {
			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}

		if ((newnameserver->conf.file = strdup(file)) == NULL) {
			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}

		if ((newnameserver->id = strdup(args[1])) == NULL) {
			ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}

		newnameserver->parent = curr_resolvers;
		newnameserver->process_responses = resolv_process_responses;
		newnameserver->conf.line = linenum;
		newnameserver->puid = curr_resolvers->nb_nameservers;
		/* the nameservers are linked backward first */
		LIST_APPEND(&curr_resolvers->nameservers, &newnameserver->list);
		curr_resolvers->nb_nameservers++;
	}
	else if (strcmp(args[0], "parse-resolv-conf") == 0) {
		err_code |= parse_resolve_conf(&errmsg, &warnmsg);
		if (err_code & ERR_WARN) {
			indent_msg(&warnmsg, 8);
			ha_warning("parsing [%s:%d]: %s\n", file, linenum, warnmsg);
			ha_free(&warnmsg);
		}
		if (err_code & ERR_ALERT) {
			indent_msg(&errmsg, 8);
			ha_alert("parsing [%s:%d]: %s\n", file, linenum, errmsg);
			ha_free(&errmsg);
			goto out;
		}
	}
	else if (strcmp(args[0], "hold") == 0) { /* hold periods */
		const char *res;
		unsigned int time;

		if (!*args[2]) {
			ha_alert("parsing [%s:%d] : '%s' expects an <event> and a <time> as arguments.\n",
				 file, linenum, args[0]);
			ha_alert("<event> can be either 'valid', 'nx', 'refused', 'timeout', or 'other'\n");
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		res = parse_time_err(args[2], &time, TIME_UNIT_MS);
		if (res == PARSE_TIME_OVER) {
			ha_alert("parsing [%s:%d]: timer overflow in argument <%s> to <%s>, maximum value is 2147483647 ms (~24.8 days).\n",
			         file, linenum, args[1], args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		else if (res == PARSE_TIME_UNDER) {
			ha_alert("parsing [%s:%d]: timer underflow in argument <%s> to <%s>, minimum non-null value is 1 ms.\n",
			         file, linenum, args[1], args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		else if (res) {
			ha_alert("parsing [%s:%d]: unexpected character '%c' in argument to <%s>.\n",
				 file, linenum, *res, args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		if (strcmp(args[1], "nx") == 0)
			curr_resolvers->hold.nx = time;
		else if (strcmp(args[1], "other") == 0)
			curr_resolvers->hold.other = time;
		else if (strcmp(args[1], "refused") == 0)
			curr_resolvers->hold.refused = time;
		else if (strcmp(args[1], "timeout") == 0)
			curr_resolvers->hold.timeout = time;
		else if (strcmp(args[1], "valid") == 0)
			curr_resolvers->hold.valid = time;
		else if (strcmp(args[1], "obsolete") == 0)
			curr_resolvers->hold.obsolete = time;
		else {
			ha_alert("parsing [%s:%d] : '%s' unknown <event>: '%s', expects either 'nx', 'timeout', 'valid', 'obsolete' or 'other'.\n",
				 file, linenum, args[0], args[1]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

	}
	else if (strcmp(args[0], "accepted_payload_size") == 0) {
		int i = 0;

		if (!*args[1]) {
			ha_alert("parsing [%s:%d] : '%s' expects <nb> as argument.\n",
				 file, linenum, args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		i = atoi(args[1]);
		if (i < DNS_HEADER_SIZE || i > DNS_MAX_UDP_MESSAGE) {
			ha_alert("parsing [%s:%d] : '%s' must be between %d and %d inclusive (was %s).\n",
				 file, linenum, args[0], DNS_HEADER_SIZE, DNS_MAX_UDP_MESSAGE, args[1]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		curr_resolvers->accepted_payload_size = i;
	}
	else if (strcmp(args[0], "resolution_pool_size") == 0) {
		ha_alert("parsing [%s:%d] : '%s' directive is not supported anymore (it never appeared in a stable release).\n",
			   file, linenum, args[0]);
		err_code |= ERR_ALERT | ERR_FATAL;
		goto out;
	}
	else if (strcmp(args[0], "resolve_retries") == 0) {
		if (!*args[1]) {
			ha_alert("parsing [%s:%d] : '%s' expects <nb> as argument.\n",
				 file, linenum, args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		curr_resolvers->resolve_retries = atoi(args[1]);
	}
	else if (strcmp(args[0], "timeout") == 0) {
		if (!*args[1]) {
			ha_alert("parsing [%s:%d] : '%s' expects 'retry' or 'resolve' and <time> as arguments.\n",
				 file, linenum, args[0]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		else if (strcmp(args[1], "retry") == 0 ||
			 strcmp(args[1], "resolve") == 0) {
			const char *res;
			unsigned int tout;

			if (!*args[2]) {
				ha_alert("parsing [%s:%d] : '%s %s' expects <time> as argument.\n",
					 file, linenum, args[0], args[1]);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}
			res = parse_time_err(args[2], &tout, TIME_UNIT_MS);
			if (res == PARSE_TIME_OVER) {
				ha_alert("parsing [%s:%d]: timer overflow in argument <%s> to <%s %s>, maximum value is 2147483647 ms (~24.8 days).\n",
					 file, linenum, args[2], args[0], args[1]);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}
			else if (res == PARSE_TIME_UNDER) {
				ha_alert("parsing [%s:%d]: timer underflow in argument <%s> to <%s %s>, minimum non-null value is 1 ms.\n",
					 file, linenum, args[2], args[0], args[1]);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}
			else if (res) {
				ha_alert("parsing [%s:%d]: unexpected character '%c' in argument to <%s %s>.\n",
					 file, linenum, *res, args[0], args[1]);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}
			if (args[1][2] == 't')
				curr_resolvers->timeout.retry = tout;
			else {
				curr_resolvers->timeout.resolve = tout;
				curr_resolvers->px->timeout.connect = tout;
			}

		}
		else {
			ha_alert("parsing [%s:%d] : '%s' expects 'retry' or 'resolve' and <time> as arguments got '%s'.\n",
				 file, linenum, args[0], args[1]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
	}
	else if (*args[0] != 0) {
		ha_alert("parsing [%s:%d] : unknown keyword '%s' in '%s' section\n", file, linenum, args[0], cursection);
		err_code |= ERR_ALERT | ERR_FATAL;
		goto out;
	}

out:
	free(errmsg);
	free(warnmsg);
	return err_code;
}

/* try to create a "default" resolvers section which uses "/etc/resolv.conf"
 *
 * This function is opportunistic and does not try to display errors or warnings.
 */
int resolvers_create_default()
{
	int err_code = ERR_NONE;

	if (global.mode & MODE_MWORKER_WAIT) /* does not create the section if in wait mode */
		return ERR_NONE;

	/* if the section already exists, do nothing */
	if (find_resolvers_by_id("default"))
		return ERR_NONE;

	curr_resolvers = NULL;
	err_code |= resolvers_new(&curr_resolvers, "default", "<internal>", 0);
	if (err_code & ERR_CODE)
		goto err;

	curr_resolvers->conf.implicit = 1;

	err_code |= parse_resolve_conf(NULL, NULL);
	if (err_code & ERR_CODE)
		goto err;
	/* check if there was any nameserver in the resolvconf file */
	if (LIST_ISEMPTY(&curr_resolvers->nameservers)) {
		err_code |= ERR_FATAL;
		goto err;
	}

err:
	if (err_code & ERR_CODE) {
		resolvers_destroy(curr_resolvers);
		curr_resolvers = NULL;
	}

	/* we never return an error there, we only try to create this section
	 * if that's possible */
	return ERR_NONE;
}

int cfg_post_parse_resolvers()
{
	int err_code = 0;
	struct server *srv;

	if (curr_resolvers) {

		/* prepare forward server descriptors */
		if (curr_resolvers->px) {
			srv = curr_resolvers->px->srv;
			while (srv) {
				/* init ssl if needed */
				if (srv->use_ssl == 1 && xprt_get(XPRT_SSL) && xprt_get(XPRT_SSL)->prepare_srv) {
					if (xprt_get(XPRT_SSL)->prepare_srv(srv)) {
						ha_alert("unable to prepare SSL for server '%s' in resolvers section '%s'.\n", srv->id, curr_resolvers->id);
						err_code |= ERR_ALERT | ERR_FATAL;
						break;
					}
				}
				srv = srv->next;
			}
		}
	}
	curr_resolvers = NULL;
	return err_code;
}

REGISTER_CONFIG_SECTION("resolvers",      cfg_parse_resolvers, cfg_post_parse_resolvers);
REGISTER_POST_DEINIT(resolvers_deinit);
REGISTER_CONFIG_POSTPARSER("dns runtime resolver", resolvers_finalize_config);
REGISTER_PRE_CHECK(resolvers_create_default);

#if defined(USE_PROMEX)

static int rslv_promex_metric_info(unsigned int id, struct promex_metric *metric, struct ist *desc)
{
	if (id >= RSLV_STAT_END)
		return -1;
	if (id == RSLV_STAT_ID  || id == RSLV_STAT_PID)
		return 0;

	*metric = (struct promex_metric){ .n = ist(resolv_stats[id].name), .type = PROMEX_MT_GAUGE, .flags = PROMEX_FL_MODULE_METRIC };
	*desc = ist(resolv_stats[id].desc);
	return 1;
}

static void *rslv_promex_start_ts(void *unused, unsigned int id)
{
	struct resolvers *resolver = LIST_NEXT(&sec_resolvers, struct resolvers *, list);

	return LIST_NEXT(&resolver->nameservers, struct dns_nameserver *, list);
}

static void *rslv_promex_next_ts(void *unused, void *metric_ctx, unsigned int id)
{
	struct dns_nameserver *ns = metric_ctx;
	struct resolvers *resolver = ns->parent;

	ns = LIST_NEXT(&ns->list, struct dns_nameserver *, list);
	if (&ns->list == &resolver->nameservers) {
		resolver = LIST_NEXT(&resolver->list, struct resolvers *, list);
		ns = ((&resolver->list == &sec_resolvers)
		      ? NULL
		      : LIST_NEXT(&resolver->nameservers, struct dns_nameserver *, list));
	}
	return ns;
}

static int rslv_promex_fill_ts(void *unused, void *metric_ctx, unsigned int id, struct promex_label *labels, struct field *field)
{
	struct dns_nameserver *ns = metric_ctx;
	struct resolvers *resolver = ns->parent;
	struct field stats[RSLV_STAT_END];
	int ret;

	labels[0].name  = ist("resolver");
	labels[0].value = ist(resolver->id);
	labels[1].name  = ist("nameserver");
	labels[1].value = ist(ns->id);

	ret = resolv_fill_stats(ns->counters, stats, &id);
	if (ret == 1)
		*field = stats[id];
	return ret;
}

static struct promex_module promex_resolver_module = {
	.name        = IST("resolver"),
	.metric_info = rslv_promex_metric_info,
	.start_ts    = rslv_promex_start_ts,
	.next_ts     = rslv_promex_next_ts,
	.fill_ts     = rslv_promex_fill_ts,
	.nb_metrics  = RSLV_STAT_END,
};

INITCALL1(STG_REGISTER, promex_register_module, &promex_resolver_module);

#endif