aboutsummaryrefslogtreecommitdiffstats
path: root/src/vnet/ethernet/arp.c
blob: 249e3b6e8cf96d8a994c1f78428412ae4ef77a17 (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
/*
 * ethernet/arp.c: IP v4 ARP node
 *
 * Copyright (c) 2010 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <vnet/ip/ip.h>
#include <vnet/ip/ip6.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ethernet/arp.h>
#include <vnet/l2/l2_input.h>
#include <vppinfra/mhash.h>
#include <vnet/fib/ip4_fib.h>
#include <vnet/fib/fib_entry_src.h>
#include <vnet/adj/adj_nbr.h>
#include <vnet/adj/adj_mcast.h>
#include <vnet/mpls/mpls.h>

/**
 * @file
 * @brief IPv4 ARP.
 *
 * This file contains code to manage the IPv4 ARP tables (IP Address
 * to MAC Address lookup).
 */


void vl_api_rpc_call_main_thread (void *fp, u8 * data, u32 data_length);

/**
 * @brief Per-interface ARP configuration and state
 */
typedef struct ethernet_arp_interface_t_
{
  /**
   * Hash table of ARP entries.
   * Since this hash table is per-interface, the key is only the IPv4 address.
   */
  uword *arp_entries;
} ethernet_arp_interface_t;

typedef struct
{
  ip4_address_t lo_addr;
  ip4_address_t hi_addr;
  u32 fib_index;
} ethernet_proxy_arp_t;

typedef struct
{
  u32 next_index;
  uword node_index;
  uword type_opaque;
  uword data;
  /* Used for arp event notification only */
  void *data_callback;
  u32 pid;
} pending_resolution_t;

typedef struct
{
  /* Hash tables mapping name to opcode. */
  uword *opcode_by_name;

  /* lite beer "glean" adjacency handling */
  uword *pending_resolutions_by_address;
  pending_resolution_t *pending_resolutions;

  /* Mac address change notification */
  uword *mac_changes_by_address;
  pending_resolution_t *mac_changes;

  ethernet_arp_ip4_entry_t *ip4_entry_pool;

  /* ARP attack mitigation */
  u32 arp_delete_rotor;
  u32 limit_arp_cache_size;

  /** Per interface state */
  ethernet_arp_interface_t *ethernet_arp_by_sw_if_index;

  /* Proxy arp vector */
  ethernet_proxy_arp_t *proxy_arps;

  uword wc_ip4_arp_publisher_node;
  uword wc_ip4_arp_publisher_et;
} ethernet_arp_main_t;

static ethernet_arp_main_t ethernet_arp_main;

typedef struct
{
  u32 sw_if_index;
  ethernet_arp_ip4_over_ethernet_address_t a;
  int is_static;
  int is_no_fib_entry;
  int flags;
#define ETHERNET_ARP_ARGS_REMOVE (1<<0)
#define ETHERNET_ARP_ARGS_FLUSH  (1<<1)
#define ETHERNET_ARP_ARGS_POPULATE  (1<<2)
#define ETHERNET_ARP_ARGS_WC_PUB  (1<<3)
} vnet_arp_set_ip4_over_ethernet_rpc_args_t;

static const u8 vrrp_prefix[] = { 0x00, 0x00, 0x5E, 0x00, 0x01 };

/* Node index for send_garp_na_process */
u32 send_garp_na_process_node_index;

static void
set_ip4_over_ethernet_rpc_callback (vnet_arp_set_ip4_over_ethernet_rpc_args_t
				    * a);

static u8 *
format_ethernet_arp_hardware_type (u8 * s, va_list * va)
{
  ethernet_arp_hardware_type_t h = va_arg (*va, ethernet_arp_hardware_type_t);
  char *t = 0;
  switch (h)
    {
#define _(n,f) case n: t = #f; break;
      foreach_ethernet_arp_hardware_type;
#undef _

    default:
      return format (s, "unknown 0x%x", h);
    }

  return format (s, "%s", t);
}

static u8 *
format_ethernet_arp_opcode (u8 * s, va_list * va)
{
  ethernet_arp_opcode_t o = va_arg (*va, ethernet_arp_opcode_t);
  char *t = 0;
  switch (o)
    {
#define _(f) case ETHERNET_ARP_OPCODE_##f: t = #f; break;
      foreach_ethernet_arp_opcode;
#undef _

    default:
      return format (s, "unknown 0x%x", o);
    }

  return format (s, "%s", t);
}

static uword
unformat_ethernet_arp_opcode_host_byte_order (unformat_input_t * input,
					      va_list * args)
{
  int *result = va_arg (*args, int *);
  ethernet_arp_main_t *am = &ethernet_arp_main;
  int x, i;

  /* Numeric opcode. */
  if (unformat (input, "0x%x", &x) || unformat (input, "%d", &x))
    {
      if (x >= (1 << 16))
	return 0;
      *result = x;
      return 1;
    }

  /* Named type. */
  if (unformat_user (input, unformat_vlib_number_by_name,
		     am->opcode_by_name, &i))
    {
      *result = i;
      return 1;
    }

  return 0;
}

static uword
unformat_ethernet_arp_opcode_net_byte_order (unformat_input_t * input,
					     va_list * args)
{
  int *result = va_arg (*args, int *);
  if (!unformat_user
      (input, unformat_ethernet_arp_opcode_host_byte_order, result))
    return 0;

  *result = clib_host_to_net_u16 ((u16) * result);
  return 1;
}

static u8 *
format_ethernet_arp_header (u8 * s, va_list * va)
{
  ethernet_arp_header_t *a = va_arg (*va, ethernet_arp_header_t *);
  u32 max_header_bytes = va_arg (*va, u32);
  u32 indent;
  u16 l2_type, l3_type;

  if (max_header_bytes != 0 && sizeof (a[0]) > max_header_bytes)
    return format (s, "ARP header truncated");

  l2_type = clib_net_to_host_u16 (a->l2_type);
  l3_type = clib_net_to_host_u16 (a->l3_type);

  indent = format_get_indent (s);

  s = format (s, "%U, type %U/%U, address size %d/%d",
	      format_ethernet_arp_opcode, clib_net_to_host_u16 (a->opcode),
	      format_ethernet_arp_hardware_type, l2_type,
	      format_ethernet_type, l3_type,
	      a->n_l2_address_bytes, a->n_l3_address_bytes);

  if (l2_type == ETHERNET_ARP_HARDWARE_TYPE_ethernet
      && l3_type == ETHERNET_TYPE_IP4)
    {
      s = format (s, "\n%U%U/%U -> %U/%U",
		  format_white_space, indent,
		  format_ethernet_address, a->ip4_over_ethernet[0].ethernet,
		  format_ip4_address, &a->ip4_over_ethernet[0].ip4,
		  format_ethernet_address, a->ip4_over_ethernet[1].ethernet,
		  format_ip4_address, &a->ip4_over_ethernet[1].ip4);
    }
  else
    {
      uword n2 = a->n_l2_address_bytes;
      uword n3 = a->n_l3_address_bytes;
      s = format (s, "\n%U%U/%U -> %U/%U",
		  format_white_space, indent,
		  format_hex_bytes, a->data + 0 * n2 + 0 * n3, n2,
		  format_hex_bytes, a->data + 1 * n2 + 0 * n3, n3,
		  format_hex_bytes, a->data + 1 * n2 + 1 * n3, n2,
		  format_hex_bytes, a->data + 2 * n2 + 1 * n3, n3);
    }

  return s;
}

u8 *
format_ethernet_arp_ip4_entry (u8 * s, va_list * va)
{
  vnet_main_t *vnm = va_arg (*va, vnet_main_t *);
  ethernet_arp_ip4_entry_t *e = va_arg (*va, ethernet_arp_ip4_entry_t *);
  vnet_sw_interface_t *si;
  u8 *flags = 0;

  if (!e)
    return format (s, "%=12s%=16s%=6s%=20s%=24s", "Time", "IP4",
		   "Flags", "Ethernet", "Interface");

  si = vnet_get_sw_interface (vnm, e->sw_if_index);

  if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC)
    flags = format (flags, "S");

  if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC)
    flags = format (flags, "D");

  if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_NO_FIB_ENTRY)
    flags = format (flags, "N");

  s = format (s, "%=12U%=16U%=6s%=20U%U",
	      format_vlib_time, vnm->vlib_main, e->time_last_updated,
	      format_ip4_address, &e->ip4_address,
	      flags ? (char *) flags : "",
	      format_ethernet_address, e->ethernet_address,
	      format_vnet_sw_interface_name, vnm, si);

  vec_free (flags);
  return s;
}

typedef struct
{
  u8 packet_data[64];
} ethernet_arp_input_trace_t;

static u8 *
format_ethernet_arp_input_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  ethernet_arp_input_trace_t *t = va_arg (*va, ethernet_arp_input_trace_t *);

  s = format (s, "%U",
	      format_ethernet_arp_header,
	      t->packet_data, sizeof (t->packet_data));

  return s;
}

static u8 *
format_arp_term_input_trace (u8 * s, va_list * va)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*va, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*va, vlib_node_t *);
  ethernet_arp_input_trace_t *t = va_arg (*va, ethernet_arp_input_trace_t *);

  /* arp-term trace data saved is either arp or ip6/icmp6 packet:
     - for arp, the 1st 16-bit field is hw type of value of 0x0001.
     - for ip6, the first nibble has value of 6. */
  s = format (s, "%U", t->packet_data[0] == 0 ?
	      format_ethernet_arp_header : format_ip6_header,
	      t->packet_data, sizeof (t->packet_data));

  return s;
}

static void
arp_nbr_probe (ip_adjacency_t * adj)
{
  vnet_main_t *vnm = vnet_get_main ();
  ip4_main_t *im = &ip4_main;
  ip_interface_address_t *ia;
  ethernet_arp_header_t *h;
  vnet_hw_interface_t *hi;
  vnet_sw_interface_t *si;
  ip4_address_t *src;
  vlib_buffer_t *b;
  vlib_main_t *vm;
  u32 bi = 0;

  vm = vlib_get_main ();

  si = vnet_get_sw_interface (vnm, adj->rewrite_header.sw_if_index);

  if (!(si->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP))
    {
      return;
    }

  src =
    ip4_interface_address_matching_destination (im,
						&adj->sub_type.nbr.next_hop.
						ip4,
						adj->rewrite_header.
						sw_if_index, &ia);
  if (!src)
    {
      return;
    }

  h =
    vlib_packet_template_get_packet (vm, &im->ip4_arp_request_packet_template,
				     &bi);

  hi = vnet_get_sup_hw_interface (vnm, adj->rewrite_header.sw_if_index);

  clib_memcpy (h->ip4_over_ethernet[0].ethernet,
	       hi->hw_address, sizeof (h->ip4_over_ethernet[0].ethernet));

  h->ip4_over_ethernet[0].ip4 = src[0];
  h->ip4_over_ethernet[1].ip4 = adj->sub_type.nbr.next_hop.ip4;

  b = vlib_get_buffer (vm, bi);
  vnet_buffer (b)->sw_if_index[VLIB_RX] =
    vnet_buffer (b)->sw_if_index[VLIB_TX] = adj->rewrite_header.sw_if_index;

  /* Add encapsulation string for software interface (e.g. ethernet header). */
  vnet_rewrite_one_header (adj[0], h, sizeof (ethernet_header_t));
  vlib_buffer_advance (b, -adj->rewrite_header.data_bytes);

  {
    vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
    u32 *to_next = vlib_frame_vector_args (f);
    to_next[0] = bi;
    f->n_vectors = 1;
    vlib_put_frame_to_node (vm, hi->output_node_index, f);
  }
}

static void
arp_mk_complete (adj_index_t ai, ethernet_arp_ip4_entry_t * e)
{
  adj_nbr_update_rewrite
    (ai, ADJ_NBR_REWRITE_FLAG_COMPLETE,
     ethernet_build_rewrite (vnet_get_main (),
			     e->sw_if_index,
			     adj_get_link_type (ai), e->ethernet_address));
}

static void
arp_mk_incomplete (adj_index_t ai)
{
  ip_adjacency_t *adj = adj_get (ai);

  adj_nbr_update_rewrite
    (ai,
     ADJ_NBR_REWRITE_FLAG_INCOMPLETE,
     ethernet_build_rewrite (vnet_get_main (),
			     adj->rewrite_header.sw_if_index,
			     VNET_LINK_ARP,
			     VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST));
}

static ethernet_arp_ip4_entry_t *
arp_entry_find (ethernet_arp_interface_t * eai, const ip4_address_t * addr)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e = NULL;
  uword *p;

  if (NULL != eai->arp_entries)
    {
      p = hash_get (eai->arp_entries, addr->as_u32);
      if (!p)
	return (NULL);

      e = pool_elt_at_index (am->ip4_entry_pool, p[0]);
    }

  return (e);
}

static adj_walk_rc_t
arp_mk_complete_walk (adj_index_t ai, void *ctx)
{
  ethernet_arp_ip4_entry_t *e = ctx;

  arp_mk_complete (ai, e);

  return (ADJ_WALK_RC_CONTINUE);
}

static adj_walk_rc_t
arp_mk_incomplete_walk (adj_index_t ai, void *ctx)
{
  arp_mk_incomplete (ai);

  return (ADJ_WALK_RC_CONTINUE);
}

void
arp_update_adjacency (vnet_main_t * vnm, u32 sw_if_index, u32 ai)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_interface_t *arp_int;
  ethernet_arp_ip4_entry_t *e;
  ip_adjacency_t *adj;

  adj = adj_get (ai);

  vec_validate (am->ethernet_arp_by_sw_if_index, sw_if_index);
  arp_int = &am->ethernet_arp_by_sw_if_index[sw_if_index];
  e = arp_entry_find (arp_int, &adj->sub_type.nbr.next_hop.ip4);

  switch (adj->lookup_next_index)
    {
    case IP_LOOKUP_NEXT_GLEAN:
      adj_glean_update_rewrite (ai);
      break;
    case IP_LOOKUP_NEXT_ARP:
      if (NULL != e)
	{
	  adj_nbr_walk_nh4 (sw_if_index,
			    &e->ip4_address, arp_mk_complete_walk, e);
	}
      else
	{
	  /*
	   * no matching ARP entry.
	   * construct the rewrite required to for an ARP packet, and stick
	   * that in the adj's pipe to smoke.
	   */
	  adj_nbr_update_rewrite
	    (ai,
	     ADJ_NBR_REWRITE_FLAG_INCOMPLETE,
	     ethernet_build_rewrite
	     (vnm,
	      sw_if_index,
	      VNET_LINK_ARP,
	      VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST));

	  /*
	   * since the FIB has added this adj for a route, it makes sense it
	   * may want to forward traffic sometime soon. Let's send a
	   * speculative ARP. just one. If we were to do periodically that
	   * wouldn't be bad either, but that's more code than i'm prepared to
	   * write at this time for relatively little reward.
	   */
	  arp_nbr_probe (adj);
	}
      break;
    case IP_LOOKUP_NEXT_MCAST:
      {
	/*
	 * Construct a partial rewrite from the known ethernet mcast dest MAC
	 */
	u8 *rewrite;
	u8 offset;

	rewrite = ethernet_build_rewrite (vnm,
					  sw_if_index,
					  adj->ia_link,
					  ethernet_ip4_mcast_dst_addr ());
	offset = vec_len (rewrite) - 2;

	/*
	 * Complete the remaining fields of the adj's rewrite to direct the
	 * complete of the rewrite at switch time by copying in the IP
	 * dst address's bytes.
	 * Ofset is 2 bytes into the MAC desintation address.
	 */
	adj_mcast_update_rewrite (ai, rewrite, offset);

	break;
      }
    case IP_LOOKUP_NEXT_DROP:
    case IP_LOOKUP_NEXT_PUNT:
    case IP_LOOKUP_NEXT_LOCAL:
    case IP_LOOKUP_NEXT_REWRITE:
    case IP_LOOKUP_NEXT_MCAST_MIDCHAIN:
    case IP_LOOKUP_NEXT_MIDCHAIN:
    case IP_LOOKUP_NEXT_ICMP_ERROR:
    case IP_LOOKUP_N_NEXT:
      ASSERT (0);
      break;
    }
}

static void
arp_adj_fib_add (ethernet_arp_ip4_entry_t * e, u32 fib_index)
{
  fib_prefix_t pfx = {
    .fp_len = 32,
    .fp_proto = FIB_PROTOCOL_IP4,
    .fp_addr.ip4 = e->ip4_address,
  };

  e->fib_entry_index =
    fib_table_entry_path_add (fib_index, &pfx, FIB_SOURCE_ADJ,
			      FIB_ENTRY_FLAG_ATTACHED,
			      DPO_PROTO_IP4, &pfx.fp_addr,
			      e->sw_if_index, ~0, 1, NULL,
			      FIB_ROUTE_PATH_FLAG_NONE);
  fib_table_lock (fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_ADJ);
}

void
arp_adj_fib_remove (ethernet_arp_ip4_entry_t * e, u32 fib_index)
{
  if (FIB_NODE_INDEX_INVALID != e->fib_entry_index)
    {
      fib_prefix_t pfx = {
	.fp_len = 32,
	.fp_proto = FIB_PROTOCOL_IP4,
	.fp_addr.ip4 = e->ip4_address,
      };
      u32 fib_index;

      fib_index = ip4_fib_table_get_index_for_sw_if_index (e->sw_if_index);

      fib_table_entry_path_remove (fib_index, &pfx,
				   FIB_SOURCE_ADJ,
				   DPO_PROTO_IP4,
				   &pfx.fp_addr,
				   e->sw_if_index, ~0, 1,
				   FIB_ROUTE_PATH_FLAG_NONE);
      fib_table_unlock (fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_ADJ);
    }
}

static ethernet_arp_ip4_entry_t *
force_reuse_arp_entry (void)
{
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_main_t *am = &ethernet_arp_main;
  u32 count = 0;
  u32 index = pool_next_index (am->ip4_entry_pool, am->arp_delete_rotor);
  if (index == ~0)		/* Try again from elt 0 */
    index = pool_next_index (am->ip4_entry_pool, index);

  /* Find a non-static random entry to free up for reuse */
  do
    {
      if ((count++ == 100) || (index == ~0))
	return NULL;		/* give up after 100 entries */
      e = pool_elt_at_index (am->ip4_entry_pool, index);
      am->arp_delete_rotor = index;
      index = pool_next_index (am->ip4_entry_pool, index);
    }
  while (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC);

  /* Remove ARP entry from its interface and update fib */
  hash_unset
    (am->ethernet_arp_by_sw_if_index[e->sw_if_index].arp_entries,
     e->ip4_address.as_u32);
  arp_adj_fib_remove
    (e, ip4_fib_table_get_index_for_sw_if_index (e->sw_if_index));
  adj_nbr_walk_nh4 (e->sw_if_index,
		    &e->ip4_address, arp_mk_incomplete_walk, NULL);
  return e;
}

static int
vnet_arp_set_ip4_over_ethernet_internal (vnet_main_t * vnm,
					 vnet_arp_set_ip4_over_ethernet_rpc_args_t
					 * args)
{
  ethernet_arp_ip4_entry_t *e = 0;
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_over_ethernet_address_t *a = &args->a;
  vlib_main_t *vm = vlib_get_main ();
  int make_new_arp_cache_entry = 1;
  uword *p;
  pending_resolution_t *pr, *mc;
  ethernet_arp_interface_t *arp_int;
  int is_static = args->is_static;
  u32 sw_if_index = args->sw_if_index;
  int is_no_fib_entry = args->is_no_fib_entry;

  vec_validate (am->ethernet_arp_by_sw_if_index, sw_if_index);

  arp_int = &am->ethernet_arp_by_sw_if_index[sw_if_index];

  if (NULL != arp_int->arp_entries)
    {
      p = hash_get (arp_int->arp_entries, a->ip4.as_u32);
      if (p)
	{
	  e = pool_elt_at_index (am->ip4_entry_pool, p[0]);

	  /* Refuse to over-write static arp. */
	  if (!is_static && (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC))
	    return -2;
	  make_new_arp_cache_entry = 0;
	}
    }

  if (make_new_arp_cache_entry)
    {
      if (am->limit_arp_cache_size &&
	  pool_elts (am->ip4_entry_pool) >= am->limit_arp_cache_size)
	{
	  e = force_reuse_arp_entry ();
	  if (NULL == e)
	    return -2;
	}
      else
	pool_get (am->ip4_entry_pool, e);

      if (NULL == arp_int->arp_entries)
	arp_int->arp_entries = hash_create (0, sizeof (u32));

      hash_set (arp_int->arp_entries, a->ip4.as_u32, e - am->ip4_entry_pool);

      e->sw_if_index = sw_if_index;
      e->ip4_address = a->ip4;
      e->fib_entry_index = FIB_NODE_INDEX_INVALID;
      clib_memcpy (e->ethernet_address,
		   a->ethernet, sizeof (e->ethernet_address));

      if (!is_no_fib_entry)
	{
	  arp_adj_fib_add (e,
			   ip4_fib_table_get_index_for_sw_if_index
			   (e->sw_if_index));
	}
      else
	{
	  e->flags |= ETHERNET_ARP_IP4_ENTRY_FLAG_NO_FIB_ENTRY;
	}
    }
  else
    {
      /*
       * prevent a DoS attack from the data-plane that
       * spams us with no-op updates to the MAC address
       */
      if (0 == memcmp (e->ethernet_address,
		       a->ethernet, sizeof (e->ethernet_address)))
	{
	  e->time_last_updated = vlib_time_now (vm);
	  goto check_customers;
	}

      /* Update time stamp and ethernet address. */
      clib_memcpy (e->ethernet_address, a->ethernet,
		   sizeof (e->ethernet_address));
    }

  e->time_last_updated = vlib_time_now (vm);
  if (is_static)
    {
      e->flags &= ~ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC;
      e->flags |= ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC;
    }
  else
    {
      e->flags &= ~ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC;
      e->flags |= ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC;
    }

  adj_nbr_walk_nh4 (sw_if_index, &e->ip4_address, arp_mk_complete_walk, e);

check_customers:
  /* Customer(s) waiting for this address to be resolved? */
  p = hash_get (am->pending_resolutions_by_address, a->ip4.as_u32);
  if (p)
    {
      u32 next_index;
      next_index = p[0];

      while (next_index != (u32) ~ 0)
	{
	  pr = pool_elt_at_index (am->pending_resolutions, next_index);
	  vlib_process_signal_event (vm, pr->node_index,
				     pr->type_opaque, pr->data);
	  next_index = pr->next_index;
	  pool_put (am->pending_resolutions, pr);
	}

      hash_unset (am->pending_resolutions_by_address, a->ip4.as_u32);
    }

  /* Customer(s) requesting ARP event for this address? */
  p = hash_get (am->mac_changes_by_address, a->ip4.as_u32);
  if (p)
    {
      u32 next_index;
      next_index = p[0];

      while (next_index != (u32) ~ 0)
	{
	  int (*fp) (u32, u8 *, u32, u32);
	  int rv = 1;
	  mc = pool_elt_at_index (am->mac_changes, next_index);
	  fp = mc->data_callback;

	  /* Call the user's data callback, return 1 to suppress dup events */
	  if (fp)
	    rv = (*fp) (mc->data, a->ethernet, sw_if_index, 0);

	  /*
	   * Signal the resolver process, as long as the user
	   * says they want to be notified
	   */
	  if (rv == 0)
	    vlib_process_signal_event (vm, mc->node_index,
				       mc->type_opaque, mc->data);
	  next_index = mc->next_index;
	}
    }

  return 0;
}

void
vnet_register_ip4_arp_resolution_event (vnet_main_t * vnm,
					void *address_arg,
					uword node_index,
					uword type_opaque, uword data)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ip4_address_t *address = address_arg;
  uword *p;
  pending_resolution_t *pr;

  pool_get (am->pending_resolutions, pr);

  pr->next_index = ~0;
  pr->node_index = node_index;
  pr->type_opaque = type_opaque;
  pr->data = data;
  pr->data_callback = 0;

  p = hash_get (am->pending_resolutions_by_address, address->as_u32);
  if (p)
    {
      /* Insert new resolution at the head of the list */
      pr->next_index = p[0];
      hash_unset (am->pending_resolutions_by_address, address->as_u32);
    }

  hash_set (am->pending_resolutions_by_address, address->as_u32,
	    pr - am->pending_resolutions);
}

int
vnet_add_del_ip4_arp_change_event (vnet_main_t * vnm,
				   void *data_callback,
				   u32 pid,
				   void *address_arg,
				   uword node_index,
				   uword type_opaque, uword data, int is_add)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ip4_address_t *address = address_arg;

  /* Try to find an existing entry */
  u32 *first = (u32 *) hash_get (am->mac_changes_by_address, address->as_u32);
  u32 *p = first;
  pending_resolution_t *mc;
  while (p && *p != ~0)
    {
      mc = pool_elt_at_index (am->mac_changes, *p);
      if (mc->node_index == node_index && mc->type_opaque == type_opaque
	  && mc->pid == pid)
	break;
      p = &mc->next_index;
    }

  int found = p && *p != ~0;
  if (is_add)
    {
      if (found)
	return VNET_API_ERROR_ENTRY_ALREADY_EXISTS;

      pool_get (am->mac_changes, mc);
      *mc = (pending_resolution_t)
      {
      .next_index = ~0,.node_index = node_index,.type_opaque =
	  type_opaque,.data = data,.data_callback = data_callback,.pid =
	  pid,};

      /* Insert new resolution at the end of the list */
      u32 new_idx = mc - am->mac_changes;
      if (p)
	p[0] = new_idx;
      else
	hash_set (am->mac_changes_by_address, address->as_u32, new_idx);
    }
  else
    {
      if (!found)
	return VNET_API_ERROR_NO_SUCH_ENTRY;

      /* Clients may need to clean up pool entries, too */
      void (*fp) (u32, u8 *) = data_callback;
      if (fp)
	(*fp) (mc->data, 0 /* no new mac addrs */ );

      /* Remove the entry from the list and delete the entry */
      *p = mc->next_index;
      pool_put (am->mac_changes, mc);

      /* Remove from hash if we deleted the last entry */
      if (*p == ~0 && p == first)
	hash_unset (am->mac_changes_by_address, address->as_u32);
    }
  return 0;
}

/* Either we drop the packet or we send a reply to the sender. */
typedef enum
{
  ARP_INPUT_NEXT_DROP,
  ARP_INPUT_NEXT_REPLY_TX,
  ARP_INPUT_N_NEXT,
} arp_input_next_t;

#define foreach_ethernet_arp_error					\
  _ (replies_sent, "ARP replies sent")					\
  _ (l2_type_not_ethernet, "L2 type not ethernet")			\
  _ (l3_type_not_ip4, "L3 type not IP4")				\
  _ (l3_src_address_not_local, "IP4 source address not local to subnet") \
  _ (l3_dst_address_not_local, "IP4 destination address not local to subnet") \
  _ (l3_src_address_is_local, "IP4 source address matches local interface") \
  _ (l3_src_address_learned, "ARP request IP4 source address learned")  \
  _ (replies_received, "ARP replies received")				\
  _ (opcode_not_request, "ARP opcode not request")                      \
  _ (proxy_arp_replies_sent, "Proxy ARP replies sent")			\
  _ (l2_address_mismatch, "ARP hw addr does not match L2 frame src addr") \
  _ (gratuitous_arp, "ARP probe or announcement dropped") \
  _ (interface_no_table, "Interface is not mapped to an IP table") \
  _ (interface_not_ip_enabled, "Interface is not IP enabled") \

typedef enum
{
#define _(sym,string) ETHERNET_ARP_ERROR_##sym,
  foreach_ethernet_arp_error
#undef _
    ETHERNET_ARP_N_ERROR,
} ethernet_arp_input_error_t;

static int
arp_unnumbered (vlib_buffer_t * p0,
		u32 input_sw_if_index, u32 conn_sw_if_index)
{
  vnet_main_t *vnm = vnet_get_main ();
  vnet_interface_main_t *vim = &vnm->interface_main;
  vnet_sw_interface_t *si;

  /* verify that the input interface is unnumbered to the connected.
   * the connected interface is the interface on which the subnet is
   * configured */
  si = &vim->sw_interfaces[input_sw_if_index];

  if (!(si->flags & VNET_SW_INTERFACE_FLAG_UNNUMBERED &&
	(si->unnumbered_sw_if_index == conn_sw_if_index)))
    {
      /* the input interface is not unnumbered to the interface on which
       * the sub-net is configured that covers the ARP request.
       * So this is not the case for unnumbered.. */
      return 0;
    }

  return !0;
}

static u32
arp_learn (vnet_main_t * vnm,
	   ethernet_arp_main_t * am, u32 sw_if_index, void *addr)
{
  vnet_arp_set_ip4_over_ethernet (vnm, sw_if_index, addr, 0, 0);
  return (ETHERNET_ARP_ERROR_l3_src_address_learned);
}

static uword
arp_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  vnet_main_t *vnm = vnet_get_main ();
  ip4_main_t *im4 = &ip4_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 n_replies_sent = 0, n_proxy_arp_replies_sent = 0;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  if (node->flags & VLIB_NODE_FLAG_TRACE)
    vlib_trace_frame_buffers_only (vm, node, from, frame->n_vectors,
				   /* stride */ 1,
				   sizeof (ethernet_arp_input_trace_t));

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  vlib_buffer_t *p0;
	  vnet_hw_interface_t *hw_if0;
	  ethernet_arp_header_t *arp0;
	  ethernet_header_t *eth_rx, *eth_tx;
	  ip4_address_t *if_addr0, proxy_src;
	  u32 pi0, error0, next0, sw_if_index0, conn_sw_if_index0, fib_index0;
	  u8 is_request0, dst_is_local0, is_unnum0, is_vrrp_reply0;
	  ethernet_proxy_arp_t *pa;
	  fib_node_index_t dst_fei, src_fei;
	  fib_prefix_t pfx0;
	  fib_entry_flag_t src_flags, dst_flags;
	  u8 *rewrite0, rewrite0_len;

	  pi0 = from[0];
	  to_next[0] = pi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;
	  pa = 0;

	  p0 = vlib_get_buffer (vm, pi0);
	  arp0 = vlib_buffer_get_current (p0);
	  /* Fill in ethernet header. */
	  eth_rx = ethernet_buffer_get_header (p0);

	  is_request0 = arp0->opcode
	    == clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request);

	  error0 = ETHERNET_ARP_ERROR_replies_sent;

	  error0 =
	    (arp0->l2_type !=
	     clib_net_to_host_u16 (ETHERNET_ARP_HARDWARE_TYPE_ethernet) ?
	     ETHERNET_ARP_ERROR_l2_type_not_ethernet : error0);
	  error0 =
	    (arp0->l3_type !=
	     clib_net_to_host_u16 (ETHERNET_TYPE_IP4) ?
	     ETHERNET_ARP_ERROR_l3_type_not_ip4 : error0);

	  sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];

	  /* not playing the ARP game if the interface is not IPv4 enabled */
	  error0 =
	    (im4->ip_enabled_by_sw_if_index[sw_if_index0] == 0 ?
	     ETHERNET_ARP_ERROR_interface_not_ip_enabled : error0);

	  if (error0)
	    goto drop2;

	  /* Check that IP address is local and matches incoming interface. */
	  fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
	  if (~0 == fib_index0)
	    {
	      error0 = ETHERNET_ARP_ERROR_interface_no_table;
	      goto drop2;

	    }
	  dst_fei = ip4_fib_table_lookup (ip4_fib_get (fib_index0),
					  &arp0->ip4_over_ethernet[1].ip4,
					  32);
	  dst_flags = fib_entry_get_flags (dst_fei);

	  conn_sw_if_index0 = fib_entry_get_resolving_interface (dst_fei);

	  /* Honor unnumbered interface, if any */
	  is_unnum0 = sw_if_index0 != conn_sw_if_index0;

	  {
	    /*
	     * we're looking for FIB entries that indicate the source
	     * is attached. There may be more specific non-attached
	     * routes that match the source, but these do not influence
	     * whether we respond to an ARP request, i.e. they do not
	     * influence whether we are the correct way for the sender
	     * to reach us, they only affect how we reach the sender.
	     */
	    fib_entry_t *src_fib_entry;
	    fib_entry_src_t *src;
	    fib_source_t source;
	    fib_prefix_t pfx;
	    int attached;
	    int mask;

	    mask = 32;
	    attached = 0;

	    do
	      {
		src_fei = ip4_fib_table_lookup (ip4_fib_get (fib_index0),
						&arp0->
						ip4_over_ethernet[0].ip4,
						mask);
		src_fib_entry = fib_entry_get (src_fei);

		/*
		 * It's possible that the source that provides the
		 * flags we need, or the flags we must not have,
		 * is not the best source, so check then all.
		 */
                /* *INDENT-OFF* */
                FOR_EACH_SRC_ADDED(src_fib_entry, src, source,
                ({
                  src_flags = fib_entry_get_flags_for_source (src_fei, source);

                  /* Reject requests/replies with our local interface
                     address. */
                  if (FIB_ENTRY_FLAG_LOCAL & src_flags)
                    {
                      error0 = ETHERNET_ARP_ERROR_l3_src_address_is_local;
                      /*
                       * When VPP has an interface whose address is also
                       * applied to a TAP interface on the host, then VPP's
                       * TAP interface will be unnumbered  to the 'real'
                       * interface and do proxy ARP from the host.
                       * The curious aspect of this setup is that ARP requests
                       * from the host will come from the VPP's own address.
                       * So don't drop immediately here, instead go see if this
                       * is a proxy ARP case.
                       */
                      goto drop1;
                    }
                  /* A Source must also be local to subnet of matching
                   * interface address. */
                  if ((FIB_ENTRY_FLAG_ATTACHED & src_flags) ||
                      (FIB_ENTRY_FLAG_CONNECTED & src_flags))
                    {
                      attached = 1;
                      break;
                    }
                  /*
                   * else
                   *  The packet was sent from an address that is not
                   *  connected nor attached i.e. it is not from an
                   *  address that is covered by a link's sub-net,
                   *  nor is it a already learned host resp.
                   */
                }));
                /* *INDENT-ON* */

		/*
		 * shorter mask lookup for the next iteration.
		 */
		fib_entry_get_prefix (src_fei, &pfx);
		mask = pfx.fp_len - 1;

		/*
		 * continue until we hit the default route or we find
		 * the attached we are looking for. The most likely
		 * outcome is we find the attached with the first source
		 * on the first lookup.
		 */
	      }
	    while (!attached &&
		   !fib_entry_is_sourced (src_fei, FIB_SOURCE_DEFAULT_ROUTE));

	    if (!attached)
	      {
		/*
		 * the matching route is a not attached, i.e. it was
		 * added as a result of routing, rather than interface/ARP
		 * configuration. If the matching route is not a host route
		 * (i.e. a /32)
		 */
		error0 = ETHERNET_ARP_ERROR_l3_src_address_not_local;
		goto drop2;
	      }
	  }

	  if (!(FIB_ENTRY_FLAG_CONNECTED & dst_flags))
	    {
	      error0 = ETHERNET_ARP_ERROR_l3_dst_address_not_local;
	      goto drop1;
	    }

	  if (sw_if_index0 != fib_entry_get_resolving_interface (src_fei))
	    {
	      /*
	       * The interface the ARP was received on is not the interface
	       * on which the covering prefix is configured. Maybe this is a
	       * case for unnumbered.
	       */
	      is_unnum0 = 1;
	    }

	  dst_is_local0 = (FIB_ENTRY_FLAG_LOCAL & dst_flags);
	  fib_entry_get_prefix (dst_fei, &pfx0);
	  if_addr0 = &pfx0.fp_addr.ip4;

	  is_vrrp_reply0 =
	    ((arp0->opcode ==
	      clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply))
	     &&
	     (!memcmp
	      (arp0->ip4_over_ethernet[0].ethernet, vrrp_prefix,
	       sizeof (vrrp_prefix))));

	  /* Trash ARP packets whose ARP-level source addresses do not
	     match their L2-frame-level source addresses, unless it's
	     a reply from a VRRP virtual router */
	  if (memcmp
	      (eth_rx->src_address, arp0->ip4_over_ethernet[0].ethernet,
	       sizeof (eth_rx->src_address)) && !is_vrrp_reply0)
	    {
	      error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
	      goto drop2;
	    }

	  /* Learn or update sender's mapping only for replies to addresses
	   * that are local to the subnet */
	  if (arp0->opcode ==
	      clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply) &&
	      dst_is_local0)
	    {
	      error0 = arp_learn (vnm, am, sw_if_index0,
				  &arp0->ip4_over_ethernet[0]);
	      goto drop1;
	    }
	  else if (arp0->opcode ==
		   clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_request) &&
		   (dst_is_local0 == 0))
	    {
	      goto drop1;
	    }

	send_reply:
	  /* Send a reply.
	     An adjacency to the sender is not always present,
	     so we use the interface to build us a rewrite string
	     which will contain all the necessary tags. */
	  rewrite0 = ethernet_build_rewrite (vnm, sw_if_index0,
					     VNET_LINK_ARP,
					     eth_rx->src_address);
	  rewrite0_len = vec_len (rewrite0);

	  /* Figure out how much to rewind current data from adjacency. */
	  vlib_buffer_advance (p0, -rewrite0_len);
	  eth_tx = vlib_buffer_get_current (p0);

	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
	  hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);

	  /* Send reply back through input interface */
	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
	  next0 = ARP_INPUT_NEXT_REPLY_TX;

	  arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply);

	  arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0];

	  clib_memcpy (arp0->ip4_over_ethernet[0].ethernet,
		       hw_if0->hw_address, 6);
	  clib_mem_unaligned (&arp0->ip4_over_ethernet[0].ip4.data_u32, u32) =
	    if_addr0->data_u32;

	  /* Hardware must be ethernet-like. */
	  ASSERT (vec_len (hw_if0->hw_address) == 6);

	  /* the rx nd tx ethernet headers wil overlap in the case
	   * when we received a tagged VLAN=0 packet, but we are sending
	   * back untagged */
	  clib_memcpy (eth_tx, rewrite0, vec_len (rewrite0));
	  vec_free (rewrite0);

	  if (NULL == pa)
	    {
	      if (is_unnum0)
		{
		  if (!arp_unnumbered (p0, sw_if_index0, conn_sw_if_index0))
		    goto drop2;
		}
	    }

	  /* We are going to reply to this request, so, in the absence of
	     errors, learn the sender */
	  if (!error0)
	    error0 = arp_learn (vnm, am, sw_if_index0,
				&arp0->ip4_over_ethernet[1]);

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, next0);

	  n_replies_sent += 1;
	  continue;

	drop1:
	  if (0 == arp0->ip4_over_ethernet[0].ip4.as_u32 ||
	      (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
	       arp0->ip4_over_ethernet[1].ip4.as_u32))
	    {
	      error0 = ETHERNET_ARP_ERROR_gratuitous_arp;
	      goto drop2;
	    }
	  /* See if proxy arp is configured for the address */
	  if (is_request0)
	    {
	      vnet_sw_interface_t *si;
	      u32 this_addr = clib_net_to_host_u32
		(arp0->ip4_over_ethernet[1].ip4.as_u32);
	      u32 fib_index0;

	      si = vnet_get_sw_interface (vnm, sw_if_index0);

	      if (!(si->flags & VNET_SW_INTERFACE_FLAG_PROXY_ARP))
		goto drop2;

	      fib_index0 = vec_elt (im4->fib_index_by_sw_if_index,
				    sw_if_index0);

	      vec_foreach (pa, am->proxy_arps)
	      {
		u32 lo_addr = clib_net_to_host_u32 (pa->lo_addr.as_u32);
		u32 hi_addr = clib_net_to_host_u32 (pa->hi_addr.as_u32);

		/* an ARP request hit in the proxy-arp table? */
		if ((this_addr >= lo_addr && this_addr <= hi_addr) &&
		    (fib_index0 == pa->fib_index))
		  {
		    proxy_src.as_u32 =
		      arp0->ip4_over_ethernet[1].ip4.data_u32;

		    /*
		     * change the interface address to the proxied
		     */
		    if_addr0 = &proxy_src;
		    is_unnum0 = 0;
		    n_proxy_arp_replies_sent++;
		    goto send_reply;
		  }
	      }
	    }

	drop2:

	  next0 = ARP_INPUT_NEXT_DROP;
	  p0->error = node->errors[error0];

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, pi0, next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_error_count (vm, node->node_index,
		    ETHERNET_ARP_ERROR_replies_sent,
		    n_replies_sent - n_proxy_arp_replies_sent);

  vlib_error_count (vm, node->node_index,
		    ETHERNET_ARP_ERROR_proxy_arp_replies_sent,
		    n_proxy_arp_replies_sent);
  return frame->n_vectors;
}

static char *ethernet_arp_error_strings[] = {
#define _(sym,string) string,
  foreach_ethernet_arp_error
#undef _
};

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (arp_input_node, static) =
{
  .function = arp_input,
  .name = "arp-input",
  .vector_size = sizeof (u32),
  .n_errors = ETHERNET_ARP_N_ERROR,
  .error_strings = ethernet_arp_error_strings,
  .n_next_nodes = ARP_INPUT_N_NEXT,
  .next_nodes = {
    [ARP_INPUT_NEXT_DROP] = "error-drop",
    [ARP_INPUT_NEXT_REPLY_TX] = "interface-output",
  },
  .format_buffer = format_ethernet_arp_header,
  .format_trace = format_ethernet_arp_input_trace,
};
/* *INDENT-ON* */

static int
ip4_arp_entry_sort (void *a1, void *a2)
{
  ethernet_arp_ip4_entry_t *e1 = a1;
  ethernet_arp_ip4_entry_t *e2 = a2;

  int cmp;
  vnet_main_t *vnm = vnet_get_main ();

  cmp = vnet_sw_interface_compare (vnm, e1->sw_if_index, e2->sw_if_index);
  if (!cmp)
    cmp = ip4_address_compare (&e1->ip4_address, &e2->ip4_address);
  return cmp;
}

ethernet_arp_ip4_entry_t *
ip4_neighbors_pool (void)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  return am->ip4_entry_pool;
}

ethernet_arp_ip4_entry_t *
ip4_neighbor_entries (u32 sw_if_index)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *n, *ns = 0;

  /* *INDENT-OFF* */
  pool_foreach (n, am->ip4_entry_pool, ({
    if (sw_if_index != ~0 && n->sw_if_index != sw_if_index)
      continue;
    vec_add1 (ns, n[0]);
  }));
  /* *INDENT-ON* */

  if (ns)
    vec_sort_with_function (ns, ip4_arp_entry_sort);
  return ns;
}

static clib_error_t *
show_ip4_arp (vlib_main_t * vm,
	      unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e, *es;
  ethernet_proxy_arp_t *pa;
  clib_error_t *error = 0;
  u32 sw_if_index;

  /* Filter entries by interface if given. */
  sw_if_index = ~0;
  (void) unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index);

  es = ip4_neighbor_entries (sw_if_index);
  if (es)
    {
      vlib_cli_output (vm, "%U", format_ethernet_arp_ip4_entry, vnm, 0);
      vec_foreach (e, es)
      {
	vlib_cli_output (vm, "%U", format_ethernet_arp_ip4_entry, vnm, e);
      }
      vec_free (es);
    }

  if (vec_len (am->proxy_arps))
    {
      vlib_cli_output (vm, "Proxy arps enabled for:");
      vec_foreach (pa, am->proxy_arps)
      {
	vlib_cli_output (vm, "Fib_index %d   %U - %U ",
			 pa->fib_index,
			 format_ip4_address, &pa->lo_addr,
			 format_ip4_address, &pa->hi_addr);
      }
    }

  return error;
}

/*?
 * Display all the IPv4 ARP entries.
 *
 * @cliexpar
 * Example of how to display the IPv4 ARP table:
 * @cliexstart{show ip arp}
 *    Time      FIB        IP4       Flags      Ethernet              Interface
 *    346.3028   0       6.1.1.3            de:ad:be:ef:ba:be   GigabitEthernet2/0/0
 *   3077.4271   0       6.1.1.4       S    de:ad:be:ef:ff:ff   GigabitEthernet2/0/0
 *   2998.6409   1       6.2.2.3            de:ad:be:ef:00:01   GigabitEthernet2/0/0
 * Proxy arps enabled for:
 * Fib_index 0   6.0.0.1 - 6.0.0.11
 * @cliexend
 ?*/
/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_ip4_arp_command, static) = {
  .path = "show ip arp",
  .function = show_ip4_arp,
  .short_help = "show ip arp",
};
/* *INDENT-ON* */

typedef struct
{
  pg_edit_t l2_type, l3_type;
  pg_edit_t n_l2_address_bytes, n_l3_address_bytes;
  pg_edit_t opcode;
  struct
  {
    pg_edit_t ethernet;
    pg_edit_t ip4;
  } ip4_over_ethernet[2];
} pg_ethernet_arp_header_t;

static inline void
pg_ethernet_arp_header_init (pg_ethernet_arp_header_t * p)
{
  /* Initialize fields that are not bit fields in the IP header. */
#define _(f) pg_edit_init (&p->f, ethernet_arp_header_t, f);
  _(l2_type);
  _(l3_type);
  _(n_l2_address_bytes);
  _(n_l3_address_bytes);
  _(opcode);
  _(ip4_over_ethernet[0].ethernet);
  _(ip4_over_ethernet[0].ip4);
  _(ip4_over_ethernet[1].ethernet);
  _(ip4_over_ethernet[1].ip4);
#undef _
}

uword
unformat_pg_arp_header (unformat_input_t * input, va_list * args)
{
  pg_stream_t *s = va_arg (*args, pg_stream_t *);
  pg_ethernet_arp_header_t *p;
  u32 group_index;

  p = pg_create_edit_group (s, sizeof (p[0]), sizeof (ethernet_arp_header_t),
			    &group_index);
  pg_ethernet_arp_header_init (p);

  /* Defaults. */
  pg_edit_set_fixed (&p->l2_type, ETHERNET_ARP_HARDWARE_TYPE_ethernet);
  pg_edit_set_fixed (&p->l3_type, ETHERNET_TYPE_IP4);
  pg_edit_set_fixed (&p->n_l2_address_bytes, 6);
  pg_edit_set_fixed (&p->n_l3_address_bytes, 4);

  if (!unformat (input, "%U: %U/%U -> %U/%U",
		 unformat_pg_edit,
		 unformat_ethernet_arp_opcode_net_byte_order, &p->opcode,
		 unformat_pg_edit,
		 unformat_ethernet_address, &p->ip4_over_ethernet[0].ethernet,
		 unformat_pg_edit,
		 unformat_ip4_address, &p->ip4_over_ethernet[0].ip4,
		 unformat_pg_edit,
		 unformat_ethernet_address, &p->ip4_over_ethernet[1].ethernet,
		 unformat_pg_edit,
		 unformat_ip4_address, &p->ip4_over_ethernet[1].ip4))
    {
      /* Free up any edits we may have added. */
      pg_free_edit_group (s);
      return 0;
    }
  return 1;
}

clib_error_t *
ip4_set_arp_limit (u32 arp_limit)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;

  am->limit_arp_cache_size = arp_limit;
  return 0;
}

/**
 * @brief Control Plane hook to remove an ARP entry
 */
int
vnet_arp_unset_ip4_over_ethernet (vnet_main_t * vnm,
				  u32 sw_if_index, void *a_arg)
{
  ethernet_arp_ip4_over_ethernet_address_t *a = a_arg;
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args;

  args.sw_if_index = sw_if_index;
  args.flags = ETHERNET_ARP_ARGS_REMOVE;
  clib_memcpy (&args.a, a, sizeof (*a));

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

/**
 * @brief Internally generated event to flush the ARP cache on an
 * interface state change event.
 * A flush will remove dynamic ARP entries, and for statics remove the MAC
 * address from the corresponding adjacencies.
 */
static int
vnet_arp_flush_ip4_over_ethernet (vnet_main_t * vnm,
				  u32 sw_if_index, void *a_arg)
{
  ethernet_arp_ip4_over_ethernet_address_t *a = a_arg;
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args;

  args.sw_if_index = sw_if_index;
  args.flags = ETHERNET_ARP_ARGS_FLUSH;
  clib_memcpy (&args.a, a, sizeof (*a));

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

/**
 * @brief Internally generated event to populate the ARP cache on an
 * interface state change event.
 * For static entries this will re-source the adjacencies.
 *
 * @param sw_if_index The interface on which the ARP entires are acted
 */
static int
vnet_arp_populate_ip4_over_ethernet (vnet_main_t * vnm,
				     u32 sw_if_index, void *a_arg)
{
  ethernet_arp_ip4_over_ethernet_address_t *a = a_arg;
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args;

  args.sw_if_index = sw_if_index;
  args.flags = ETHERNET_ARP_ARGS_POPULATE;
  clib_memcpy (&args.a, a, sizeof (*a));

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

/**
 * @brief publish wildcard arp event
 * @param sw_if_index The interface on which the ARP entires are acted
 */
static int
vnet_arp_wc_publish (u32 sw_if_index, void *a_arg)
{
  ethernet_arp_ip4_over_ethernet_address_t *a = a_arg;
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args = {
    .flags = ETHERNET_ARP_ARGS_WC_PUB,
    .sw_if_index = sw_if_index,
    .a = *a
  };

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

static void
vnet_arp_wc_publish_internal (vnet_main_t * vnm,
			      vnet_arp_set_ip4_over_ethernet_rpc_args_t *
			      args)
{
  vlib_main_t *vm = vlib_get_main ();
  ethernet_arp_main_t *am = &ethernet_arp_main;
  uword ni = am->wc_ip4_arp_publisher_node;
  uword et = am->wc_ip4_arp_publisher_et;

  if (ni == (uword) ~ 0)
    return;
  wc_arp_report_t *r =
    vlib_process_signal_event_data (vm, ni, et, 1, sizeof *r);
  r->ip4 = args->a.ip4.as_u32;
  r->sw_if_index = args->sw_if_index;
  memcpy (r->mac, args->a.ethernet, sizeof r->mac);
}

void
wc_arp_set_publisher_node (uword node_index, uword event_type)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  am->wc_ip4_arp_publisher_node = node_index;
  am->wc_ip4_arp_publisher_et = event_type;
}

/*
 * arp_add_del_interface_address
 *
 * callback when an interface address is added or deleted
 */
static void
arp_add_del_interface_address (ip4_main_t * im,
			       uword opaque,
			       u32 sw_if_index,
			       ip4_address_t * address,
			       u32 address_length,
			       u32 if_address_index, u32 is_del)
{
  /*
   * Flush the ARP cache of all entries covered by the address
   * that is being removed.
   */
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= sw_if_index)
    return;

  if (is_del)
    {
      ethernet_arp_interface_t *eai;
      u32 i, *to_delete = 0;
      hash_pair_t *pair;

      eai = &am->ethernet_arp_by_sw_if_index[sw_if_index];

      /* *INDENT-OFF* */
      hash_foreach_pair (pair, eai->arp_entries,
      ({
	e = pool_elt_at_index(am->ip4_entry_pool,
			      pair->value[0]);
	if (ip4_destination_matches_route (im, &e->ip4_address,
					   address, address_length))
	  {
	    vec_add1 (to_delete, e - am->ip4_entry_pool);
	  }
      }));
      /* *INDENT-ON* */

      for (i = 0; i < vec_len (to_delete); i++)
	{
	  ethernet_arp_ip4_over_ethernet_address_t delme;
	  e = pool_elt_at_index (am->ip4_entry_pool, to_delete[i]);

	  clib_memcpy (&delme.ethernet, e->ethernet_address, 6);
	  delme.ip4.as_u32 = e->ip4_address.as_u32;

	  vnet_arp_flush_ip4_over_ethernet (vnet_get_main (),
					    e->sw_if_index, &delme);
	}

      vec_free (to_delete);
    }
}

static void
arp_table_bind (ip4_main_t * im,
		uword opaque,
		u32 sw_if_index, u32 new_fib_index, u32 old_fib_index)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_interface_t *eai;
  ethernet_arp_ip4_entry_t *e;
  hash_pair_t *pair;

  /*
   * the IP table that the interface is bound to has changed.
   * reinstall all the adj fibs.
   */

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= sw_if_index)
    return;

  eai = &am->ethernet_arp_by_sw_if_index[sw_if_index];

  /* *INDENT-OFF* */
  hash_foreach_pair (pair, eai->arp_entries,
  ({
    e = pool_elt_at_index(am->ip4_entry_pool,
                          pair->value[0]);
    /*
     * remove the adj-fib from the old table and add to the new
     */
    arp_adj_fib_remove(e, old_fib_index);
    arp_adj_fib_add(e, new_fib_index);
  }));
  /* *INDENT-ON* */

}

static clib_error_t *
ethernet_arp_init (vlib_main_t * vm)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ip4_main_t *im = &ip4_main;
  clib_error_t *error;
  pg_node_t *pn;

  if ((error = vlib_call_init_function (vm, ethernet_init)))
    return error;

  ethernet_register_input_type (vm, ETHERNET_TYPE_ARP, arp_input_node.index);

  pn = pg_get_node (arp_input_node.index);
  pn->unformat_edit = unformat_pg_arp_header;

  am->opcode_by_name = hash_create_string (0, sizeof (uword));
#define _(o) hash_set_mem (am->opcode_by_name, #o, ETHERNET_ARP_OPCODE_##o);
  foreach_ethernet_arp_opcode;
#undef _

  /* $$$ configurable */
  am->limit_arp_cache_size = 50000;

  am->pending_resolutions_by_address = hash_create (0, sizeof (uword));
  am->mac_changes_by_address = hash_create (0, sizeof (uword));
  am->wc_ip4_arp_publisher_node = (uword) ~ 0;

  /* don't trace ARP error packets */
  {
    vlib_node_runtime_t *rt =
      vlib_node_get_runtime (vm, arp_input_node.index);

#define _(a,b)                                  \
    vnet_pcap_drop_trace_filter_add_del         \
        (rt->errors[ETHERNET_ARP_ERROR_##a],    \
         1 /* is_add */);
    foreach_ethernet_arp_error
#undef _
  }

  ip4_add_del_interface_address_callback_t cb;
  cb.function = arp_add_del_interface_address;
  cb.function_opaque = 0;
  vec_add1 (im->add_del_interface_address_callbacks, cb);

  ip4_table_bind_callback_t cbt;
  cbt.function = arp_table_bind;
  cbt.function_opaque = 0;
  vec_add1 (im->table_bind_callbacks, cbt);

  return 0;
}

VLIB_INIT_FUNCTION (ethernet_arp_init);

static void
arp_entry_free (ethernet_arp_interface_t * eai, ethernet_arp_ip4_entry_t * e)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;

  arp_adj_fib_remove
    (e, ip4_fib_table_get_index_for_sw_if_index (e->sw_if_index));
  hash_unset (eai->arp_entries, e->ip4_address.as_u32);
  pool_put (am->ip4_entry_pool, e);
}

static inline int
vnet_arp_unset_ip4_over_ethernet_internal (vnet_main_t * vnm,
					   vnet_arp_set_ip4_over_ethernet_rpc_args_t
					   * args)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_interface_t *eai;

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= args->sw_if_index)
    return 0;

  eai = &am->ethernet_arp_by_sw_if_index[args->sw_if_index];

  e = arp_entry_find (eai, &args->a.ip4);

  if (NULL != e)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_incomplete_walk, NULL);
      arp_entry_free (eai, e);
    }

  return 0;
}

static int
vnet_arp_flush_ip4_over_ethernet_internal (vnet_main_t * vnm,
					   vnet_arp_set_ip4_over_ethernet_rpc_args_t
					   * args)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_interface_t *eai;

  if (vec_len (am->ethernet_arp_by_sw_if_index) <= args->sw_if_index)
    return 0;

  eai = &am->ethernet_arp_by_sw_if_index[args->sw_if_index];

  e = arp_entry_find (eai, &args->a.ip4);

  if (NULL != e)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_incomplete_walk, e);

      /*
       * The difference between flush and unset, is that an unset
       * means delete for static and dynamic entries. A flush
       * means delete only for dynamic. Flushing is what the DP
       * does in response to interface events. unset is only done
       * by the control plane.
       */
      if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_STATIC)
	{
	  e->flags &= ~ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC;
	}
      else if (e->flags & ETHERNET_ARP_IP4_ENTRY_FLAG_DYNAMIC)
	{
	  arp_entry_free (eai, e);
	}
    }
  return (0);
}

static int
vnet_arp_populate_ip4_over_ethernet_internal (vnet_main_t * vnm,
					      vnet_arp_set_ip4_over_ethernet_rpc_args_t
					      * args)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  ethernet_arp_interface_t *eai;

  vec_validate (am->ethernet_arp_by_sw_if_index, args->sw_if_index);
  eai = &am->ethernet_arp_by_sw_if_index[args->sw_if_index];

  e = arp_entry_find (eai, &args->a.ip4);

  if (NULL != e)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_complete_walk, e);
    }
  return (0);
}

static void
set_ip4_over_ethernet_rpc_callback (vnet_arp_set_ip4_over_ethernet_rpc_args_t
				    * a)
{
  vnet_main_t *vm = vnet_get_main ();
  ASSERT (vlib_get_thread_index () == 0);

  if (a->flags & ETHERNET_ARP_ARGS_REMOVE)
    vnet_arp_unset_ip4_over_ethernet_internal (vm, a);
  else if (a->flags & ETHERNET_ARP_ARGS_FLUSH)
    vnet_arp_flush_ip4_over_ethernet_internal (vm, a);
  else if (a->flags & ETHERNET_ARP_ARGS_POPULATE)
    vnet_arp_populate_ip4_over_ethernet_internal (vm, a);
  else if (a->flags & ETHERNET_ARP_ARGS_WC_PUB)
    vnet_arp_wc_publish_internal (vm, a);
  else
    vnet_arp_set_ip4_over_ethernet_internal (vm, a);
}

/**
 * @brief Invoked when the interface's admin state changes
 */
static clib_error_t *
ethernet_arp_sw_interface_up_down (vnet_main_t * vnm,
				   u32 sw_if_index, u32 flags)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  u32 i, *to_delete = 0;

  /* *INDENT-OFF* */
  pool_foreach (e, am->ip4_entry_pool,
  ({
    if (e->sw_if_index == sw_if_index)
      vec_add1 (to_delete,
		e - am->ip4_entry_pool);
  }));
  /* *INDENT-ON* */

  for (i = 0; i < vec_len (to_delete); i++)
    {
      ethernet_arp_ip4_over_ethernet_address_t delme;
      e = pool_elt_at_index (am->ip4_entry_pool, to_delete[i]);

      clib_memcpy (&delme.ethernet, e->ethernet_address, 6);
      delme.ip4.as_u32 = e->ip4_address.as_u32;

      if (flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP)
	{
	  vnet_arp_populate_ip4_over_ethernet (vnm, e->sw_if_index, &delme);
	}
      else
	{
	  vnet_arp_flush_ip4_over_ethernet (vnm, e->sw_if_index, &delme);
	}

    }
  vec_free (to_delete);

  return 0;
}

VNET_SW_INTERFACE_ADMIN_UP_DOWN_FUNCTION (ethernet_arp_sw_interface_up_down);

static void
increment_ip4_and_mac_address (ethernet_arp_ip4_over_ethernet_address_t * a)
{
  u8 old;
  int i;

  for (i = 3; i >= 0; i--)
    {
      old = a->ip4.as_u8[i];
      a->ip4.as_u8[i] += 1;
      if (old < a->ip4.as_u8[i])
	break;
    }

  for (i = 5; i >= 0; i--)
    {
      old = a->ethernet[i];
      a->ethernet[i] += 1;
      if (old < a->ethernet[i])
	break;
    }
}

int
vnet_arp_set_ip4_over_ethernet (vnet_main_t * vnm,
				u32 sw_if_index, void *a_arg,
				int is_static, int is_no_fib_entry)
{
  ethernet_arp_ip4_over_ethernet_address_t *a = a_arg;
  vnet_arp_set_ip4_over_ethernet_rpc_args_t args;

  args.sw_if_index = sw_if_index;
  args.is_static = is_static;
  args.is_no_fib_entry = is_no_fib_entry;
  args.flags = 0;
  clib_memcpy (&args.a, a, sizeof (*a));

  vl_api_rpc_call_main_thread (set_ip4_over_ethernet_rpc_callback,
			       (u8 *) & args, sizeof (args));
  return 0;
}

void
proxy_arp_walk (proxy_arp_walk_t cb, void *data)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_proxy_arp_t *pa;

  vec_foreach (pa, am->proxy_arps)
  {
    if (!cb (&pa->lo_addr, &pa->hi_addr, pa->fib_index, data))
      break;
  }
}

int
vnet_proxy_arp_add_del (ip4_address_t * lo_addr,
			ip4_address_t * hi_addr, u32 fib_index, int is_del)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_proxy_arp_t *pa;
  u32 found_at_index = ~0;

  vec_foreach (pa, am->proxy_arps)
  {
    if (pa->lo_addr.as_u32 == lo_addr->as_u32 &&
	pa->hi_addr.as_u32 == hi_addr->as_u32 && pa->fib_index == fib_index)
      {
	found_at_index = pa - am->proxy_arps;
	break;
      }
  }

  if (found_at_index != ~0)
    {
      /* Delete, otherwise it's already in the table */
      if (is_del)
	vec_delete (am->proxy_arps, 1, found_at_index);
      return 0;
    }
  /* delete, no such entry */
  if (is_del)
    return VNET_API_ERROR_NO_SUCH_ENTRY;

  /* add, not in table */
  vec_add2 (am->proxy_arps, pa, 1);
  pa->lo_addr.as_u32 = lo_addr->as_u32;
  pa->hi_addr.as_u32 = hi_addr->as_u32;
  pa->fib_index = fib_index;
  return 0;
}

/*
 * Remove any proxy arp entries asdociated with the
 * specificed fib.
 */
int
vnet_proxy_arp_fib_reset (u32 fib_id)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_proxy_arp_t *pa;
  u32 *entries_to_delete = 0;
  u32 fib_index;
  int i;

  fib_index = fib_table_find (FIB_PROTOCOL_IP4, fib_id);
  if (~0 == fib_index)
    return VNET_API_ERROR_NO_SUCH_ENTRY;

  vec_foreach (pa, am->proxy_arps)
  {
    if (pa->fib_index == fib_index)
      {
	vec_add1 (entries_to_delete, pa - am->proxy_arps);
      }
  }

  for (i = 0; i < vec_len (entries_to_delete); i++)
    {
      vec_delete (am->proxy_arps, 1, entries_to_delete[i]);
    }

  vec_free (entries_to_delete);

  return 0;
}

static clib_error_t *
ip_arp_add_del_command_fn (vlib_main_t * vm,
			   unformat_input_t * input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 sw_if_index;
  ethernet_arp_ip4_over_ethernet_address_t lo_addr, hi_addr, addr;
  int addr_valid = 0;
  int is_del = 0;
  int count = 1;
  u32 fib_index = 0;
  u32 fib_id;
  int is_static = 0;
  int is_no_fib_entry = 0;
  int is_proxy = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      /* set ip arp TenGigE1/1/0/1 1.2.3.4 aa:bb:... or aabb.ccdd... */
      if (unformat (input, "%U %U %U",
		    unformat_vnet_sw_interface, vnm, &sw_if_index,
		    unformat_ip4_address, &addr.ip4,
		    unformat_ethernet_address, &addr.ethernet))
	addr_valid = 1;

      else if (unformat (input, "delete") || unformat (input, "del"))
	is_del = 1;

      else if (unformat (input, "static"))
	is_static = 1;

      else if (unformat (input, "no-fib-entry"))
	is_no_fib_entry = 1;

      else if (unformat (input, "count %d", &count))
	;

      else if (unformat (input, "fib-id %d", &fib_id))
	{
	  fib_index = fib_table_find (FIB_PROTOCOL_IP4, fib_id);

	  if (~0 == fib_index)
	    return clib_error_return (0, "fib ID %d doesn't exist\n", fib_id);
	}

      else if (unformat (input, "proxy %U - %U",
			 unformat_ip4_address, &lo_addr.ip4,
			 unformat_ip4_address, &hi_addr.ip4))
	is_proxy = 1;
      else
	break;
    }

  if (is_proxy)
    {
      (void) vnet_proxy_arp_add_del (&lo_addr.ip4, &hi_addr.ip4,
				     fib_index, is_del);
      return 0;
    }

  if (addr_valid)
    {
      int i;

      for (i = 0; i < count; i++)
	{
	  if (is_del == 0)
	    {
	      uword event_type, *event_data = 0;

	      /* Park the debug CLI until the arp entry is installed */
	      vnet_register_ip4_arp_resolution_event
		(vnm, &addr.ip4, vlib_current_process (vm),
		 1 /* type */ , 0 /* data */ );

	      vnet_arp_set_ip4_over_ethernet
		(vnm, sw_if_index, &addr, is_static, is_no_fib_entry);

	      vlib_process_wait_for_event (vm);
	      event_type = vlib_process_get_events (vm, &event_data);
	      vec_reset_length (event_data);
	      if (event_type != 1)
		clib_warning ("event type %d unexpected", event_type);
	    }
	  else
	    vnet_arp_unset_ip4_over_ethernet (vnm, sw_if_index, &addr);

	  increment_ip4_and_mac_address (&addr);
	}
    }
  else
    {
      return clib_error_return (0, "unknown input `%U'",
				format_unformat_error, input);
    }

  return 0;
}

/* *INDENT-OFF* */
/*?
 * Add or delete IPv4 ARP cache entries.
 *
 * @note 'set ip arp' options (e.g. delete, static, 'fib-id <id>',
 * 'count <number>', 'interface ip4_addr mac_addr') can be added in
 * any order and combination.
 *
 * @cliexpar
 * @parblock
 * Add or delete IPv4 ARP cache entries as follows. MAC Address can be in
 * either aa:bb:cc:dd:ee:ff format or aabb.ccdd.eeff format.
 * @cliexcmd{set ip arp GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @cliexcmd{set ip arp delete GigabitEthernet2/0/0 6.0.0.3 de:ad:be:ef:ba:be}
 *
 * To add or delete an IPv4 ARP cache entry to or from a specific fib
 * table:
 * @cliexcmd{set ip arp fib-id 1 GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @cliexcmd{set ip arp fib-id 1 delete GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 *
 * Add or delete IPv4 static ARP cache entries as follows:
 * @cliexcmd{set ip arp static GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @cliexcmd{set ip arp static delete GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 *
 * For testing / debugging purposes, the 'set ip arp' command can add or
 * delete multiple entries. Supply the 'count N' parameter:
 * @cliexcmd{set ip arp count 10 GigabitEthernet2/0/0 6.0.0.3 dead.beef.babe}
 * @endparblock
 ?*/
VLIB_CLI_COMMAND (ip_arp_add_del_command, static) = {
  .path = "set ip arp",
  .short_help =
  "set ip arp [del] <intfc> <ip-address> <mac-address> [static] [no-fib-entry] [count <count>] [fib-id <fib-id>] [proxy <lo-addr> - <hi-addr>]",
  .function = ip_arp_add_del_command_fn,
};
/* *INDENT-ON* */

static clib_error_t *
set_int_proxy_arp_command_fn (vlib_main_t * vm,
			      unformat_input_t *
			      input, vlib_cli_command_t * cmd)
{
  vnet_main_t *vnm = vnet_get_main ();
  u32 sw_if_index;
  vnet_sw_interface_t *si;
  int enable = 0;
  int intfc_set = 0;

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "%U", unformat_vnet_sw_interface,
		    vnm, &sw_if_index))
	intfc_set = 1;
      else if (unformat (input, "enable") || unformat (input, "on"))
	enable = 1;
      else if (unformat (input, "disable") || unformat (input, "off"))
	enable = 0;
      else
	break;
    }

  if (intfc_set == 0)
    return clib_error_return (0, "unknown input '%U'",
			      format_unformat_error, input);

  si = vnet_get_sw_interface (vnm, sw_if_index);
  ASSERT (si);
  if (enable)
    si->flags |= VNET_SW_INTERFACE_FLAG_PROXY_ARP;
  else
    si->flags &= ~VNET_SW_INTERFACE_FLAG_PROXY_ARP;

  return 0;
}

/* *INDENT-OFF* */
/*?
 * Enable proxy-arp on an interface. The vpp stack will answer ARP
 * requests for the indicated address range. Multiple proxy-arp
 * ranges may be provisioned.
 *
 * @note Proxy ARP as a technology is infamous for blackholing traffic.
 * Also, the underlying implementation has not been performance-tuned.
 * Avoid creating an unnecessarily large set of ranges.
 *
 * @cliexpar
 * To enable proxy arp on a range of addresses, use:
 * @cliexcmd{set ip arp proxy 6.0.0.1 - 6.0.0.11}
 * Append 'del' to delete a range of proxy ARP addresses:
 * @cliexcmd{set ip arp proxy 6.0.0.1 - 6.0.0.11 del}
 * You must then specifically enable proxy arp on individual interfaces:
 * @cliexcmd{set interface proxy-arp GigabitEthernet0/8/0 enable}
 * To disable proxy arp on an individual interface:
 * @cliexcmd{set interface proxy-arp GigabitEthernet0/8/0 disable}
 ?*/
VLIB_CLI_COMMAND (set_int_proxy_enable_command, static) = {
  .path = "set interface proxy-arp",
  .short_help =
  "set interface proxy-arp <intfc> [enable|disable]",
  .function = set_int_proxy_arp_command_fn,
};
/* *INDENT-ON* */


/*
 * ARP/ND Termination in a L2 Bridge Domain based on IP4/IP6 to MAC
 * hash tables mac_by_ip4 and mac_by_ip6 for each BD.
 */
typedef enum
{
  ARP_TERM_NEXT_L2_OUTPUT,
  ARP_TERM_NEXT_DROP,
  ARP_TERM_N_NEXT,
} arp_term_next_t;

u32 arp_term_next_node_index[32];

static uword
arp_term_l2bd (vlib_main_t * vm,
	       vlib_node_runtime_t * node, vlib_frame_t * frame)
{
  l2input_main_t *l2im = &l2input_main;
  u32 n_left_from, next_index, *from, *to_next;
  u32 n_replies_sent = 0;
  u16 last_bd_index = ~0;
  l2_bridge_domain_t *last_bd_config = 0;
  l2_input_config_t *cfg0;

  from = vlib_frame_vector_args (frame);
  n_left_from = frame->n_vectors;
  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  vlib_buffer_t *p0;
	  ethernet_header_t *eth0;
	  ethernet_arp_header_t *arp0;
	  ip6_header_t *iph0;
	  u8 *l3h0;
	  u32 pi0, error0, next0, sw_if_index0;
	  u16 ethertype0;
	  u16 bd_index0;
	  u32 ip0;
	  u8 *macp0;
	  u8 is_vrrp_reply0;

	  pi0 = from[0];
	  to_next[0] = pi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  p0 = vlib_get_buffer (vm, pi0);
	  // Terminate only local (SHG == 0) ARP
	  if (vnet_buffer (p0)->l2.shg != 0)
	    goto next_l2_feature;

	  eth0 = vlib_buffer_get_current (p0);
	  l3h0 = (u8 *) eth0 + vnet_buffer (p0)->l2.l2_len;
	  ethertype0 = clib_net_to_host_u16 (*(u16 *) (l3h0 - 2));
	  arp0 = (ethernet_arp_header_t *) l3h0;

	  if (PREDICT_FALSE ((ethertype0 != ETHERNET_TYPE_ARP) ||
			     (arp0->opcode !=
			      clib_host_to_net_u16
			      (ETHERNET_ARP_OPCODE_request))))
	    goto check_ip6_nd;

	  /* Must be ARP request packet here */
	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
			     (p0->flags & VLIB_BUFFER_IS_TRACED)))
	    {
	      u8 *t0 = vlib_add_trace (vm, node, p0,
				       sizeof (ethernet_arp_input_trace_t));
	      clib_memcpy (t0, l3h0, sizeof (ethernet_arp_input_trace_t));
	    }

	  error0 = ETHERNET_ARP_ERROR_replies_sent;
	  error0 =
	    (arp0->l2_type !=
	     clib_net_to_host_u16 (ETHERNET_ARP_HARDWARE_TYPE_ethernet)
	     ? ETHERNET_ARP_ERROR_l2_type_not_ethernet : error0);
	  error0 =
	    (arp0->l3_type !=
	     clib_net_to_host_u16 (ETHERNET_TYPE_IP4) ?
	     ETHERNET_ARP_ERROR_l3_type_not_ip4 : error0);

	  sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];

	  if (error0)
	    goto drop;

	  is_vrrp_reply0 =
	    ((arp0->opcode ==
	      clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply))
	     &&
	     (!memcmp
	      (arp0->ip4_over_ethernet[0].ethernet, vrrp_prefix,
	       sizeof (vrrp_prefix))));

	  /* Trash ARP packets whose ARP-level source addresses do not
	     match their L2-frame-level source addresses, unless it's
	     a reply from a VRRP virtual router */
	  if (PREDICT_FALSE
	      (memcmp (eth0->src_address, arp0->ip4_over_ethernet[0].ethernet,
		       sizeof (eth0->src_address)) && !is_vrrp_reply0))
	    {
	      error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
	      goto drop;
	    }

	  /* Check if anyone want ARP request events for L2 BDs */
	  {
	    ethernet_arp_main_t *am = &ethernet_arp_main;
	    if (am->wc_ip4_arp_publisher_node != (uword) ~ 0)
	      vnet_arp_wc_publish (sw_if_index0, &arp0->ip4_over_ethernet[0]);
	  }

	  /* lookup BD mac_by_ip4 hash table for MAC entry */
	  ip0 = arp0->ip4_over_ethernet[1].ip4.as_u32;
	  bd_index0 = vnet_buffer (p0)->l2.bd_index;
	  if (PREDICT_FALSE ((bd_index0 != last_bd_index)
			     || (last_bd_index == (u16) ~ 0)))
	    {
	      last_bd_index = bd_index0;
	      last_bd_config = vec_elt_at_index (l2im->bd_configs, bd_index0);
	    }
	  macp0 = (u8 *) hash_get (last_bd_config->mac_by_ip4, ip0);

	  if (PREDICT_FALSE (!macp0))
	    goto next_l2_feature;	/* MAC not found */

	  /* MAC found, send ARP reply -
	     Convert ARP request packet to ARP reply */
	  arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply);
	  arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0];
	  arp0->ip4_over_ethernet[0].ip4.as_u32 = ip0;
	  clib_memcpy (arp0->ip4_over_ethernet[0].ethernet, macp0, 6);
	  clib_memcpy (eth0->dst_address, eth0->src_address, 6);
	  clib_memcpy (eth0->src_address, macp0, 6);
	  n_replies_sent += 1;

	output_response:
	  /* For BVI, need to use l2-fwd node to send ARP reply as
	     l2-output node cannot output packet to BVI properly */
	  cfg0 = vec_elt_at_index (l2im->configs, sw_if_index0);
	  if (PREDICT_FALSE (cfg0->bvi))
	    {
	      vnet_buffer (p0)->l2.feature_bitmap |= L2INPUT_FEAT_FWD;
	      vnet_buffer (p0)->sw_if_index[VLIB_RX] = 0;
	      goto next_l2_feature;
	    }

	  /* Send ARP/ND reply back out input interface through l2-output */
	  vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
	  next0 = ARP_TERM_NEXT_L2_OUTPUT;
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next, pi0,
					   next0);
	  continue;

	check_ip6_nd:
	  /* IP6 ND event notification or solicitation handling to generate
	     local response instead of flooding */
	  iph0 = (ip6_header_t *) l3h0;
	  if (PREDICT_FALSE (ethertype0 == ETHERNET_TYPE_IP6 &&
			     iph0->protocol == IP_PROTOCOL_ICMP6 &&
			     !ip6_address_is_unspecified
			     (&iph0->src_address)))
	    {
	      sw_if_index0 = vnet_buffer (p0)->sw_if_index[VLIB_RX];
	      if (vnet_ip6_nd_term
		  (vm, node, p0, eth0, iph0, sw_if_index0,
		   vnet_buffer (p0)->l2.bd_index))
		goto output_response;
	    }

	next_l2_feature:
	  {
	    next0 = vnet_l2_feature_next (p0, arp_term_next_node_index,
					  L2INPUT_FEAT_ARP_TERM);
	    vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					     to_next, n_left_to_next,
					     pi0, next0);
	    continue;
	  }

	drop:
	  if (0 == arp0->ip4_over_ethernet[0].ip4.as_u32 ||
	      (arp0->ip4_over_ethernet[0].ip4.as_u32 ==
	       arp0->ip4_over_ethernet[1].ip4.as_u32))
	    {
	      error0 = ETHERNET_ARP_ERROR_gratuitous_arp;
	    }
	  next0 = ARP_TERM_NEXT_DROP;
	  p0->error = node->errors[error0];

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next, pi0,
					   next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  vlib_error_count (vm, node->node_index,
		    ETHERNET_ARP_ERROR_replies_sent, n_replies_sent);
  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (arp_term_l2bd_node, static) = {
  .function = arp_term_l2bd,
  .name = "arp-term-l2bd",
  .vector_size = sizeof (u32),
  .n_errors = ETHERNET_ARP_N_ERROR,
  .error_strings = ethernet_arp_error_strings,
  .n_next_nodes = ARP_TERM_N_NEXT,
  .next_nodes = {
    [ARP_TERM_NEXT_L2_OUTPUT] = "l2-output",
    [ARP_TERM_NEXT_DROP] = "error-drop",
  },
  .format_buffer = format_ethernet_arp_header,
  .format_trace = format_arp_term_input_trace,
};
/* *INDENT-ON* */

clib_error_t *
arp_term_init (vlib_main_t * vm)
{
  // Initialize the feature next-node indexes
  feat_bitmap_init_next_nodes (vm,
			       arp_term_l2bd_node.index,
			       L2INPUT_N_FEAT,
			       l2input_get_feat_names (),
			       arp_term_next_node_index);
  return 0;
}

VLIB_INIT_FUNCTION (arp_term_init);

void
change_arp_mac (u32 sw_if_index, ethernet_arp_ip4_entry_t * e)
{
  if (e->sw_if_index == sw_if_index)
    {
      adj_nbr_walk_nh4 (e->sw_if_index,
			&e->ip4_address, arp_mk_complete_walk, e);
    }
}

void
ethernet_arp_change_mac (u32 sw_if_index)
{
  ethernet_arp_main_t *am = &ethernet_arp_main;
  ethernet_arp_ip4_entry_t *e;
  adj_index_t ai;

  /* *INDENT-OFF* */
  pool_foreach (e, am->ip4_entry_pool,
  ({
    change_arp_mac (sw_if_index, e);
  }));
  /* *INDENT-ON* */

  ai = adj_glean_get (FIB_PROTOCOL_IP4, sw_if_index);

  if (ADJ_INDEX_INVALID != ai)
    adj_glean_update_rewrite (ai);
}

void
send_ip4_garp (vlib_main_t * vm, const vnet_hw_interface_t * hi)
{
  ip4_main_t *i4m = &ip4_main;
  ip4_address_t *ip4_addr =
    ip4_interface_first_address (i4m, hi->sw_if_index, 0);

  send_ip4_garp_w_addr (vm, ip4_addr, hi);
}

void
send_ip4_garp_w_addr (vlib_main_t * vm,
		      const ip4_address_t * ip4_addr,
		      const vnet_hw_interface_t * hi)
{
  ip4_main_t *i4m = &ip4_main;
  u32 sw_if_index = hi->sw_if_index;

  if (ip4_addr)
    {
      clib_warning ("Sending GARP for IP4 address %U on sw_if_idex %d",
		    format_ip4_address, ip4_addr, sw_if_index);

      /* Form GARP packet for output - Gratuitous ARP is an ARP request packet
         where the interface IP/MAC pair is used for both source and request
         MAC/IP pairs in the request */
      u32 bi = 0;
      ethernet_arp_header_t *h = vlib_packet_template_get_packet
	(vm, &i4m->ip4_arp_request_packet_template, &bi);
      clib_memcpy (h->ip4_over_ethernet[0].ethernet, hi->hw_address,
		   sizeof (h->ip4_over_ethernet[0].ethernet));
      clib_memcpy (h->ip4_over_ethernet[1].ethernet, hi->hw_address,
		   sizeof (h->ip4_over_ethernet[1].ethernet));
      h->ip4_over_ethernet[0].ip4 = ip4_addr[0];
      h->ip4_over_ethernet[1].ip4 = ip4_addr[0];

      /* Setup MAC header with ARP Etype and broadcast DMAC */
      vlib_buffer_t *b = vlib_get_buffer (vm, bi);
      vlib_buffer_advance (b, -sizeof (ethernet_header_t));
      ethernet_header_t *e = vlib_buffer_get_current (b);
      e->type = clib_host_to_net_u16 (ETHERNET_TYPE_ARP);
      clib_memcpy (e->src_address, hi->hw_address, sizeof (e->src_address));
      memset (e->dst_address, 0xff, sizeof (e->dst_address));

      /* Send GARP packet out the specified interface */
      vnet_buffer (b)->sw_if_index[VLIB_RX] =
	vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
      vlib_frame_t *f = vlib_get_frame_to_node (vm, hi->output_node_index);
      u32 *to_next = vlib_frame_vector_args (f);
      to_next[0] = bi;
      f->n_vectors = 1;
      vlib_put_frame_to_node (vm, hi->output_node_index, f);
    }
}

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */