summaryrefslogtreecommitdiff
path: root/proto/bgp/bgp.c
blob: 8bacebfc278a547a7f97dd53e699f3c03a6f9d3c (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
/*
 *	BIRD -- The Border Gateway Protocol
 *
 *	(c) 2000 Martin Mares <mj@ucw.cz>
 *	(c) 2008--2016 Ondrej Zajicek <santiago@crfreenet.org>
 *	(c) 2008--2016 CZ.NIC z.s.p.o.
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

/**
 * DOC: Border Gateway Protocol
 *
 * The BGP protocol is implemented in three parts: |bgp.c| which takes care of
 * the connection and most of the interface with BIRD core, |packets.c| handling
 * both incoming and outgoing BGP packets and |attrs.c| containing functions for
 * manipulation with BGP attribute lists.
 *
 * As opposed to the other existing routing daemons, BIRD has a sophisticated
 * core architecture which is able to keep all the information needed by BGP in
 * the primary routing table, therefore no complex data structures like a
 * central BGP table are needed. This increases memory footprint of a BGP router
 * with many connections, but not too much and, which is more important, it
 * makes BGP much easier to implement.
 *
 * Each instance of BGP (corresponding to a single BGP peer) is described by a
 * &bgp_proto structure to which are attached individual connections represented
 * by &bgp_connection (usually, there exists only one connection, but during BGP
 * session setup, there can be more of them). The connections are handled
 * according to the BGP state machine defined in the RFC with all the timers and
 * all the parameters configurable.
 *
 * In incoming direction, we listen on the connection's socket and each time we
 * receive some input, we pass it to bgp_rx(). It decodes packet headers and the
 * markers and passes complete packets to bgp_rx_packet() which distributes the
 * packet according to its type.
 *
 * In outgoing direction, we gather all the routing updates and sort them to
 * buckets (&bgp_bucket) according to their attributes (we keep a hash table for
 * fast comparison of &rta's and a &fib which helps us to find if we already
 * have another route for the same destination queued for sending, so that we
 * can replace it with the new one immediately instead of sending both
 * updates). There also exists a special bucket holding all the route
 * withdrawals which cannot be queued anywhere else as they don't have any
 * attributes. If we have any packet to send (due to either new routes or the
 * connection tracking code wanting to send a Open, Keepalive or Notification
 * message), we call bgp_schedule_packet() which sets the corresponding bit in a
 * @packet_to_send bit field in &bgp_conn and as soon as the transmit socket
 * buffer becomes empty, we call bgp_fire_tx(). It inspects state of all the
 * packet type bits and calls the corresponding bgp_create_xx() functions,
 * eventually rescheduling the same packet type if we have more data of the same
 * type to send.
 *
 * The processing of attributes consists of two functions: bgp_decode_attrs()
 * for checking of the attribute blocks and translating them to the language of
 * BIRD's extended attributes and bgp_encode_attrs() which does the
 * converse. Both functions are built around a @bgp_attr_table array describing
 * all important characteristics of all known attributes.  Unknown transitive
 * attributes are attached to the route as %EAF_TYPE_OPAQUE byte streams.
 *
 * BGP protocol implements graceful restart in both restarting (local restart)
 * and receiving (neighbor restart) roles. The first is handled mostly by the
 * graceful restart code in the nest, BGP protocol just handles capabilities,
 * sets @gr_wait and locks graceful restart until end-of-RIB mark is received.
 * The second is implemented by internal restart of the BGP state to %BS_IDLE
 * and protocol state to %PS_START, but keeping the protocol up from the core
 * point of view and therefore maintaining received routes. Routing table
 * refresh cycle (rt_refresh_begin(), rt_refresh_end()) is used for removing
 * stale routes after reestablishment of BGP session during graceful restart.
 *
 * Supported standards:
 * RFC 4271 - Border Gateway Protocol 4 (BGP)
 * RFC 1997 - BGP Communities Attribute
 * RFC 2385 - Protection of BGP Sessions via TCP MD5 Signature
 * RFC 2545 - Use of BGP Multiprotocol Extensions for IPv6
 * RFC 2918 - Route Refresh Capability
 * RFC 3107 - Carrying Label Information in BGP
 * RFC 4360 - BGP Extended Communities Attribute
 * RFC 4364 - BGP/MPLS IPv4 Virtual Private Networks
 * RFC 4456 - BGP Route Reflection
 * RFC 4486 - Subcodes for BGP Cease Notification Message
 * RFC 4659 - BGP/MPLS IPv6 Virtual Private Networks
 * RFC 4724 - Graceful Restart Mechanism for BGP
 * RFC 4760 - Multiprotocol extensions for BGP
 * RFC 4798 - Connecting IPv6 Islands over IPv4 MPLS
 * RFC 5065 - AS confederations for BGP
 * RFC 5082 - Generalized TTL Security Mechanism
 * RFC 5492 - Capabilities Advertisement with BGP
 * RFC 5549 - Advertising IPv4 NLRI with an IPv6 Next Hop
 * RFC 5575 - Dissemination of Flow Specification Rules
 * RFC 5668 - 4-Octet AS Specific BGP Extended Community
 * RFC 6286 - AS-Wide Unique BGP Identifier
 * RFC 6608 - Subcodes for BGP Finite State Machine Error
 * RFC 6793 - BGP Support for 4-Octet AS Numbers
 * RFC 7311 - Accumulated IGP Metric Attribute for BGP
 * RFC 7313 - Enhanced Route Refresh Capability for BGP
 * RFC 7606 - Revised Error Handling for BGP UPDATE Messages
 * RFC 7911 - Advertisement of Multiple Paths in BGP
 * RFC 7947 - Internet Exchange BGP Route Server
 * RFC 8092 - BGP Large Communities Attribute
 * RFC 8203 - BGP Administrative Shutdown Communication
 * RFC 8212 - Default EBGP Route Propagation Behavior without Policies
 * RFC 8654 - Extended Message Support for BGP
 * RFC 9117 - Revised Validation Procedure for BGP Flow Specifications
 * RFC 9234 - Route Leak Prevention and Detection Using Roles
 * draft-ietf-idr-ext-opt-param-07
 * draft-uttaro-idr-bgp-persistence-04
 * draft-walton-bgp-hostname-capability-02
 */

#undef LOCAL_DEBUG

#include <stdlib.h>

#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/rt.h"
#include "nest/cli.h"
#include "nest/locks.h"
#include "conf/conf.h"
#include "filter/filter.h"
#include "lib/socket.h"
#include "lib/resource.h"
#include "lib/string.h"

#include "bgp.h"


static list STATIC_LIST_INIT(bgp_sockets);		/* Global list of listening sockets */


static void bgp_connect(struct bgp_proto *p);
static void bgp_active(struct bgp_proto *p);
static void bgp_setup_conn(struct bgp_proto *p, struct bgp_conn *conn);
static void bgp_setup_sk(struct bgp_conn *conn, sock *s);
static void bgp_send_open(struct bgp_conn *conn);
static void bgp_update_bfd(struct bgp_proto *p, const struct bfd_options *bfd);

static int bgp_incoming_connection(sock *sk, uint dummy UNUSED);
static void bgp_listen_sock_err(sock *sk UNUSED, int err);

static void bgp_graceful_restart_feed(struct bgp_channel *c);


/**
 * bgp_open - open a BGP instance
 * @p: BGP instance
 *
 * This function allocates and configures shared BGP resources, mainly listening
 * sockets. Should be called as the last step during initialization (when lock
 * is acquired and neighbor is ready). When error, caller should change state to
 * PS_DOWN and return immediately.
 */
static int
bgp_open(struct bgp_proto *p)
{
  struct bgp_socket *bs = NULL;
  struct iface *ifa = p->cf->strict_bind ? p->cf->iface : NULL;
  ip_addr addr = p->cf->strict_bind ? p->cf->local_ip :
    (p->ipv4 ? IPA_NONE4 : IPA_NONE6);
  uint port = p->cf->local_port;
  uint flags = p->cf->free_bind ? SKF_FREEBIND : 0;
  uint flag_mask = SKF_FREEBIND;

  /* We assume that cf->iface is defined iff cf->local_ip is link-local */

  WALK_LIST(bs, bgp_sockets)
    if (ipa_equal(bs->sk->saddr, addr) &&
	(bs->sk->sport == port) &&
	(bs->sk->iface == ifa) &&
	(bs->sk->vrf == p->p.vrf) &&
	((bs->sk->flags & flag_mask) == flags))
    {
      bs->uc++;
      p->sock = bs;
      return 0;
    }

  sock *sk = sk_new(proto_pool);
  sk->type = SK_TCP_PASSIVE;
  sk->ttl = 255;
  sk->saddr = addr;
  sk->sport = port;
  sk->iface = ifa;
  sk->vrf = p->p.vrf;
  sk->flags = flags;
  sk->tos = IP_PREC_INTERNET_CONTROL;
  sk->rbsize = BGP_RX_BUFFER_SIZE;
  sk->tbsize = BGP_TX_BUFFER_SIZE;
  sk->rx_hook = bgp_incoming_connection;
  sk->err_hook = bgp_listen_sock_err;

  if (sk_open(sk) < 0)
    goto err;

  bs = mb_allocz(proto_pool, sizeof(struct bgp_socket));
  bs->sk = sk;
  bs->uc = 1;
  p->sock = bs;
  sk->data = bs;

  add_tail(&bgp_sockets, &bs->n);

  return 0;

err:
  sk_log_error(sk, p->p.name);
  log(L_ERR "%s: Cannot open listening socket", p->p.name);
  rfree(sk);
  return -1;
}

/**
 * bgp_close - close a BGP instance
 * @p: BGP instance
 *
 * This function frees and deconfigures shared BGP resources.
 */
static void
bgp_close(struct bgp_proto *p)
{
  struct bgp_socket *bs = p->sock;

  ASSERT(bs && bs->uc);

  if (--bs->uc)
    return;

  rfree(bs->sk);
  rem_node(&bs->n);
  mb_free(bs);
}

static inline int
bgp_setup_auth(struct bgp_proto *p, int enable)
{
  if (p->cf->password)
  {
    ip_addr prefix = p->cf->remote_ip;
    int pxlen = -1;

    if (p->cf->remote_range)
    {
      prefix = net_prefix(p->cf->remote_range);
      pxlen = net_pxlen(p->cf->remote_range);
    }

    int rv = sk_set_md5_auth(p->sock->sk,
			     p->cf->local_ip, prefix, pxlen, p->cf->iface,
			     enable ? p->cf->password : NULL, p->cf->setkey);

    if (rv < 0)
      sk_log_error(p->sock->sk, p->p.name);

    return rv;
  }
  else
    return 0;
}

static inline struct bgp_channel *
bgp_find_channel(struct bgp_proto *p, u32 afi)
{
  struct bgp_channel *c;
  WALK_LIST(c, p->p.channels)
    if (c->afi == afi)
      return c;

  return NULL;
}

static void
bgp_startup(struct bgp_proto *p)
{
  BGP_TRACE(D_EVENTS, "Started");
  p->start_state = BSS_CONNECT;

  if (!p->passive)
    bgp_active(p);

  if (p->postponed_sk)
  {
    /* Apply postponed incoming connection */
    bgp_setup_conn(p, &p->incoming_conn);
    bgp_setup_sk(&p->incoming_conn, p->postponed_sk);
    bgp_send_open(&p->incoming_conn);
    p->postponed_sk = NULL;
  }
}

static void
bgp_startup_timeout(timer *t)
{
  bgp_startup(t->data);
}


static void
bgp_initiate(struct bgp_proto *p)
{
  int err_val;

  if (bgp_open(p) < 0)
  { err_val = BEM_NO_SOCKET; goto err1; }

  if (bgp_setup_auth(p, 1) < 0)
  { err_val = BEM_INVALID_MD5; goto err2; }

  if (p->cf->bfd)
    bgp_update_bfd(p, p->cf->bfd);

  if (p->startup_delay)
  {
    p->start_state = BSS_DELAY;
    BGP_TRACE(D_EVENTS, "Startup delayed by %d seconds due to errors", p->startup_delay);
    bgp_start_timer(p->startup_timer, p->startup_delay);
  }
  else
    bgp_startup(p);

  return;

err2:
  bgp_close(p);
err1:
  p->p.disabled = 1;
  bgp_store_error(p, NULL, BE_MISC, err_val);

  p->neigh = NULL;
  proto_notify_state(&p->p, PS_DOWN);

  return;
}

/**
 * bgp_start_timer - start a BGP timer
 * @t: timer
 * @value: time (in seconds) to fire (0 to disable the timer)
 *
 * This functions calls tm_start() on @t with time @value and the amount of
 * randomization suggested by the BGP standard. Please use it for all BGP
 * timers.
 */
void
bgp_start_timer(timer *t, uint value)
{
  if (value)
  {
    /* The randomization procedure is specified in RFC 4271 section 10 */
    btime time = value S;
    btime randomize = random() % ((time / 4) + 1);
    tm_start(t, time - randomize);
  }
  else
    tm_stop(t);
}

/**
 * bgp_close_conn - close a BGP connection
 * @conn: connection to close
 *
 * This function takes a connection described by the &bgp_conn structure, closes
 * its socket and frees all resources associated with it.
 */
void
bgp_close_conn(struct bgp_conn *conn)
{
  // struct bgp_proto *p = conn->bgp;

  DBG("BGP: Closing connection\n");
  conn->packets_to_send = 0;
  conn->channels_to_send = 0;
  rfree(conn->connect_timer);
  conn->connect_timer = NULL;
  rfree(conn->keepalive_timer);
  conn->keepalive_timer = NULL;
  rfree(conn->hold_timer);
  conn->hold_timer = NULL;

  rfree(conn->tx_ev);
  conn->tx_ev = NULL;
  rfree(conn->sk);
  conn->sk = NULL;

  mb_free(conn->local_caps);
  conn->local_caps = NULL;
  mb_free(conn->remote_caps);
  conn->remote_caps = NULL;
}


/**
 * bgp_update_startup_delay - update a startup delay
 * @p: BGP instance
 *
 * This function updates a startup delay that is used to postpone next BGP
 * connect. It also handles disable_after_error and might stop BGP instance
 * when error happened and disable_after_error is on.
 *
 * It should be called when BGP protocol error happened.
 */
void
bgp_update_startup_delay(struct bgp_proto *p)
{
  const struct bgp_config *cf = p->cf;

  DBG("BGP: Updating startup delay\n");

  if (p->last_proto_error && ((current_time() - p->last_proto_error) >= cf->error_amnesia_time S))
    p->startup_delay = 0;

  p->last_proto_error = current_time();

  if (cf->disable_after_error)
  {
    p->startup_delay = 0;
    p->p.disabled = 1;
    return;
  }

  if (!p->startup_delay)
    p->startup_delay = cf->error_delay_time_min;
  else
    p->startup_delay = MIN(2 * p->startup_delay, cf->error_delay_time_max);
}

static void
bgp_graceful_close_conn(struct bgp_conn *conn, int subcode, byte *data, uint len)
{
  switch (conn->state)
  {
  case BS_IDLE:
  case BS_CLOSE:
    return;

  case BS_CONNECT:
  case BS_ACTIVE:
    bgp_conn_enter_idle_state(conn);
    return;

  case BS_OPENSENT:
  case BS_OPENCONFIRM:
  case BS_ESTABLISHED:
    if (subcode < 0)
    {
      bgp_conn_enter_close_state(conn);
      bgp_schedule_packet(conn, NULL, PKT_SCHEDULE_CLOSE);
    }
    else
      bgp_error(conn, 6, subcode, data, len);
    return;

  default:
    bug("bgp_graceful_close_conn: Unknown state %d", conn->state);
  }
}

static void
bgp_down(struct bgp_proto *p)
{
  if (p->start_state > BSS_PREPARE)
  {
    bgp_setup_auth(p, 0);
    bgp_close(p);
  }

  p->neigh = NULL;

  BGP_TRACE(D_EVENTS, "Down");
  proto_notify_state(&p->p, PS_DOWN);
}

static void
bgp_decision(void *vp)
{
  struct bgp_proto *p = vp;

  DBG("BGP: Decision start\n");
  if ((p->p.proto_state == PS_START) &&
      (p->outgoing_conn.state == BS_IDLE) &&
      (p->incoming_conn.state != BS_OPENCONFIRM) &&
      !p->passive)
    bgp_active(p);

  if ((p->p.proto_state == PS_STOP) &&
      (p->outgoing_conn.state == BS_IDLE) &&
      (p->incoming_conn.state == BS_IDLE))
    bgp_down(p);
}

static struct bgp_proto *
bgp_spawn(struct bgp_proto *pp, ip_addr remote_ip)
{
  struct symbol *sym;
  char fmt[SYM_MAX_LEN];

  bsprintf(fmt, "%s%%0%dd", pp->cf->dynamic_name, pp->cf->dynamic_name_digits);

  /* This is hack, we would like to share config, but we need to copy it now */
  new_config = config;
  cfg_mem = config->mem;
  conf_this_scope = config->root_scope;
  sym = cf_default_name(fmt, &(pp->dynamic_name_counter));
  proto_clone_config(sym, pp->p.cf);
  new_config = NULL;
  cfg_mem = NULL;

  /* Just pass remote_ip to bgp_init() */
  ((struct bgp_config *) sym->proto)->remote_ip = remote_ip;

  return (void *) proto_spawn(sym->proto, 0);
}

void
bgp_stop(struct bgp_proto *p, int subcode, byte *data, uint len)
{
  proto_notify_state(&p->p, PS_STOP);
  p->uncork_ev->data = NULL;
  bgp_graceful_close_conn(&p->outgoing_conn, subcode, data, len);
  bgp_graceful_close_conn(&p->incoming_conn, subcode, data, len);

  struct bgp_channel *c;
  WALK_LIST(c, p->p.channels)
    if (c->ptx)
      bgp_free_pending_tx(c);

  ev_schedule(p->event);
}

static inline void
bgp_conn_set_state(struct bgp_conn *conn, uint new_state)
{
  if (conn->bgp->p.mrtdump & MD_STATES)
    bgp_dump_state_change(conn, conn->state, new_state);

  conn->state = new_state;
}

void
bgp_conn_enter_openconfirm_state(struct bgp_conn *conn)
{
  /* Really, most of the work is done in bgp_rx_open(). */
  bgp_conn_set_state(conn, BS_OPENCONFIRM);
}

static const struct bgp_af_caps dummy_af_caps = { };
static const struct bgp_af_caps basic_af_caps = { .ready = 1 };

void
bgp_conn_enter_established_state(struct bgp_conn *conn)
{
  struct bgp_proto *p = conn->bgp;
  struct bgp_caps *local = conn->local_caps;
  struct bgp_caps *peer = conn->remote_caps;
  struct bgp_channel *c;

  BGP_TRACE(D_EVENTS, "BGP session established");
  p->last_established = current_time();
  p->stats.fsm_established_transitions++;

  /* For multi-hop BGP sessions */
  if (ipa_zero(p->local_ip))
    p->local_ip = conn->sk->saddr;

  /* For promiscuous sessions */
  if (!p->remote_as)
    p->remote_as = conn->received_as;

  /* In case of LLv6 is not valid during BGP start */
  if (ipa_zero(p->link_addr) && p->neigh && p->neigh->iface && p->neigh->iface->llv6)
    p->link_addr = p->neigh->iface->llv6->ip;

  conn->sk->fast_rx = 0;

  p->conn = conn;
  p->last_error_class = 0;
  p->last_error_code = 0;

  p->as4_session = conn->as4_session;

  p->route_refresh = peer->route_refresh;
  p->enhanced_refresh = local->enhanced_refresh && peer->enhanced_refresh;

  /* Whether we may handle possible GR/LLGR of peer (it has some AF GR-able) */
  p->gr_ready = p->llgr_ready = 0;	/* Updated later */

  /* Whether peer is ready to handle our GR recovery */
  int peer_gr_ready = peer->gr_aware && !(peer->gr_flags & BGP_GRF_RESTART);

  if (p->gr_active_num)
    tm_stop(p->gr_timer);

  /* Number of active channels */
  int num = 0;

  /* Summary state of ADD_PATH RX for active channels */
  uint summary_add_path_rx = 0;

  WALK_LIST(c, p->p.channels)
  {
    const struct bgp_af_caps *loc = bgp_find_af_caps(local, c->afi);
    const struct bgp_af_caps *rem = bgp_find_af_caps(peer,  c->afi);

    /* Use default if capabilities were not announced */
    if (!local->length && (c->afi == BGP_AF_IPV4))
      loc = &basic_af_caps;

    if (!peer->length && (c->afi == BGP_AF_IPV4))
      rem = &basic_af_caps;

    /* Ignore AFIs that were not announced in multiprotocol capability */
    if (!loc || !loc->ready)
      loc = &dummy_af_caps;

    if (!rem || !rem->ready)
      rem = &dummy_af_caps;

    int active = loc->ready && rem->ready;
    c->c.disabled = !active;
    c->c.reloadable = p->route_refresh || c->cf->import_table;

    c->index = active ? num++ : 0;

    c->feed_state = BFS_NONE;
    c->load_state = BFS_NONE;

    /* Channels where peer may do GR */
    uint gr_ready = active && local->gr_aware && rem->gr_able;
    uint llgr_ready = active && local->llgr_aware && rem->llgr_able;

    c->gr_ready = gr_ready || llgr_ready;
    p->gr_ready = p->gr_ready || c->gr_ready;
    p->llgr_ready = p->llgr_ready || llgr_ready;

    /* Remember last LLGR stale time */
    c->stale_time = local->llgr_aware ? rem->llgr_time : 0;

    /* Channels not able to recover gracefully */
    if (p->p.gr_recovery && (!active || !peer_gr_ready))
      channel_graceful_restart_unlock(&c->c);

    /* Channels waiting for local convergence */
    if (p->p.gr_recovery && loc->gr_able && peer_gr_ready)
      c->c.gr_wait = 1;

    /* Channels where regular graceful restart failed */
    if ((c->gr_active == BGP_GRS_ACTIVE) &&
	!(active && rem->gr_able && (rem->gr_af_flags & BGP_GRF_FORWARDING)))
      bgp_graceful_restart_done(c);

    /* Channels where regular long-lived restart failed */
    if ((c->gr_active == BGP_GRS_LLGR) &&
	!(active && rem->llgr_able && (rem->gr_af_flags & BGP_LLGRF_FORWARDING)))
      bgp_graceful_restart_done(c);

    /* GR capability implies that neighbor will send End-of-RIB */
    if (peer->gr_aware)
      c->load_state = BFS_LOADING;

    c->ext_next_hop = c->cf->ext_next_hop && (bgp_channel_is_ipv6(c) || rem->ext_next_hop);
    c->add_path_rx = (loc->add_path & BGP_ADD_PATH_RX) && (rem->add_path & BGP_ADD_PATH_TX);
    c->add_path_tx = (loc->add_path & BGP_ADD_PATH_TX) && (rem->add_path & BGP_ADD_PATH_RX);

    if (active)
      summary_add_path_rx |= !c->add_path_rx ? 1 : 2;

    /* Update RA mode */
    if (c->add_path_tx)
      c->c.ra_mode = RA_ANY;
    else if (c->cf->secondary)
      c->c.ra_mode = RA_ACCEPTED;
    else
      c->c.ra_mode = RA_OPTIMAL;
  }

  p->afi_map = mb_alloc(p->p.pool, num * sizeof(u32));
  p->channel_map = mb_alloc(p->p.pool, num * sizeof(void *));
  p->channel_count = num;
  p->summary_add_path_rx = summary_add_path_rx;

  WALK_LIST(c, p->p.channels)
  {
    if (c->c.disabled)
      continue;

    p->afi_map[c->index] = c->afi;
    p->channel_map[c->index] = c;
  }

  /* proto_notify_state() will likely call bgp_feed_begin(), setting c->feed_state */

  bgp_conn_set_state(conn, BS_ESTABLISHED);
  proto_notify_state(&p->p, PS_UP);
}

static void
bgp_conn_leave_established_state(struct bgp_proto *p)
{
  BGP_TRACE(D_EVENTS, "BGP session closed");
  p->last_established = current_time();
  p->conn = NULL;

  if (p->p.proto_state == PS_UP)
    bgp_stop(p, 0, NULL, 0);
}

void
bgp_conn_enter_close_state(struct bgp_conn *conn)
{
  struct bgp_proto *p = conn->bgp;
  int os = conn->state;

  bgp_conn_set_state(conn, BS_CLOSE);
  tm_stop(conn->keepalive_timer);
  conn->sk->rx_hook = NULL;

  /* Timeout for CLOSE state, if we cannot send notification soon then we just hangup */
  bgp_start_timer(conn->hold_timer, 10);

  if (os == BS_ESTABLISHED)
    bgp_conn_leave_established_state(p);
}

void
bgp_conn_enter_idle_state(struct bgp_conn *conn)
{
  struct bgp_proto *p = conn->bgp;
  int os = conn->state;

  bgp_close_conn(conn);
  bgp_conn_set_state(conn, BS_IDLE);
  ev_schedule(p->event);

  if (os == BS_ESTABLISHED)
    bgp_conn_leave_established_state(p);
}

/**
 * bgp_handle_graceful_restart - handle detected BGP graceful restart
 * @p: BGP instance
 *
 * This function is called when a BGP graceful restart of the neighbor is
 * detected (when the TCP connection fails or when a new TCP connection
 * appears). The function activates processing of the restart - starts routing
 * table refresh cycle and activates BGP restart timer. The protocol state goes
 * back to %PS_START, but changing BGP state back to %BS_IDLE is left for the
 * caller.
 */
void
bgp_handle_graceful_restart(struct bgp_proto *p)
{
  ASSERT(p->conn && (p->conn->state == BS_ESTABLISHED) && p->gr_ready);

  BGP_TRACE(D_EVENTS, "Neighbor graceful restart detected%s",
	    p->gr_active_num ? " - already pending" : "");

  p->gr_active_num = 0;

  struct bgp_channel *c;
  WALK_LIST(c, p->p.channels)
  {
    /* FIXME: perhaps check for channel state instead of disabled flag? */
    if (c->c.disabled)
      continue;

    if (c->gr_ready)
    {
      p->gr_active_num++;

      switch (c->gr_active)
      {
      case BGP_GRS_NONE:
	c->gr_active = BGP_GRS_ACTIVE;
	rt_refresh_begin(&c->c.in_req);
	break;

      case BGP_GRS_ACTIVE:
	rt_refresh_end(&c->c.in_req);
	rt_refresh_begin(&c->c.in_req);
	break;

      case BGP_GRS_LLGR:
	rt_refresh_begin(&c->c.in_req);
	bgp_graceful_restart_feed(c);
	break;
      }
    }
    else
    {
      /* Just flush the routes */
      rt_refresh_begin(&c->c.in_req);
      rt_refresh_end(&c->c.in_req);
    }

    /* Reset bucket and prefix tables */
    bgp_free_pending_tx(c);
    bgp_init_pending_tx(c);
    c->packets_to_send = 0;
  }

  /* p->gr_ready -> at least one active channel is c->gr_ready */
  ASSERT(p->gr_active_num > 0);

  proto_notify_state(&p->p, PS_START);
  tm_start(p->gr_timer, p->conn->remote_caps->gr_time S);
}

static void
bgp_graceful_restart_feed_done(struct rt_export_request *req)
{
  req->hook = NULL;
}

static void
bgp_graceful_restart_feed_dump_req(struct rt_export_request *req)
{
  struct bgp_channel *c = SKIP_BACK(struct bgp_channel, stale_feed, req);
  debug("  BGP-GR %s.%s export request %p\n", c->c.proto->name, c->c.name, req);
}

static void
bgp_graceful_restart_feed_log_state_change(struct rt_export_request *req, u8 state)
{
  struct bgp_channel *c = SKIP_BACK(struct bgp_channel, stale_feed, req);
  struct bgp_proto *p = (void *) c->c.proto;
  BGP_TRACE(D_EVENTS, "Long-lived graceful restart export state changed to %s", rt_export_state_name(state));

  if (state == TES_READY)
    rt_stop_export(req, bgp_graceful_restart_feed_done);
}

static void
bgp_graceful_restart_drop_export(struct rt_export_request *req UNUSED, const net_addr *n UNUSED, struct rt_pending_export *rpe UNUSED)
{ /* Nothing to do */ }

static void
bgp_graceful_restart_feed(struct bgp_channel *c)
{
  c->stale_feed = (struct rt_export_request) {
    .name = "BGP-GR",
    .list = &global_work_list,
    .trace_routes = c->c.debug | c->c.proto->debug,
    .dump_req = bgp_graceful_restart_feed_dump_req,
    .log_state_change = bgp_graceful_restart_feed_log_state_change,
    .export_bulk = bgp_rte_modify_stale,
    .export_one = bgp_graceful_restart_drop_export,
  };

  rt_request_export(c->c.table, &c->stale_feed);
}




/**
 * bgp_graceful_restart_done - finish active BGP graceful restart
 * @c: BGP channel
 *
 * This function is called when the active BGP graceful restart of the neighbor
 * should be finished for channel @c - either successfully (the neighbor sends
 * all paths and reports end-of-RIB for given AFI/SAFI on the new session) or
 * unsuccessfully (the neighbor does not support BGP graceful restart on the new
 * session). The function ends the routing table refresh cycle.
 */
void
bgp_graceful_restart_done(struct bgp_channel *c)
{
  struct bgp_proto *p = (void *) c->c.proto;

  ASSERT(c->gr_active);
  c->gr_active = 0;
  p->gr_active_num--;

  if (!p->gr_active_num)
    BGP_TRACE(D_EVENTS, "Neighbor graceful restart done");

  tm_stop(c->stale_timer);
  rt_refresh_end(&c->c.in_req);
}

/**
 * bgp_graceful_restart_timeout - timeout of graceful restart 'restart timer'
 * @t: timer
 *
 * This function is a timeout hook for @gr_timer, implementing BGP restart time
 * limit for reestablisment of the BGP session after the graceful restart. When
 * fired, we just proceed with the usual protocol restart.
 */

static void
bgp_graceful_restart_timeout(timer *t)
{
  struct bgp_proto *p = t->data;

  BGP_TRACE(D_EVENTS, "Neighbor graceful restart timeout");

  if (p->llgr_ready)
  {
    struct bgp_channel *c;
    WALK_LIST(c, p->p.channels)
    {
      /* Channel is not in GR and is already flushed */
      if (!c->gr_active)
	continue;

      /* Channel is already in LLGR from past restart */
      if (c->gr_active == BGP_GRS_LLGR)
	continue;

      /* Channel is in GR, but does not support LLGR -> stop GR */
      if (!c->stale_time)
      {
	bgp_graceful_restart_done(c);
	continue;
      }

      /* Channel is in GR, and supports LLGR -> start LLGR */
      c->gr_active = BGP_GRS_LLGR;
      tm_start(c->stale_timer, c->stale_time S);
      bgp_graceful_restart_feed(c);
    }
  }
  else
    bgp_stop(p, 0, NULL, 0);
}

static void
bgp_long_lived_stale_timeout(timer *t)
{
  struct bgp_channel *c = t->data;
  struct bgp_proto *p = (void *) c->c.proto;

  BGP_TRACE(D_EVENTS, "Long-lived stale timeout");

  bgp_graceful_restart_done(c);
}


/**
 * bgp_refresh_begin - start incoming enhanced route refresh sequence
 * @c: BGP channel
 *
 * This function is called when an incoming enhanced route refresh sequence is
 * started by the neighbor, demarcated by the BoRR packet. The function updates
 * the load state and starts the routing table refresh cycle. Note that graceful
 * restart also uses routing table refresh cycle, but RFC 7313 and load states
 * ensure that these two sequences do not overlap.
 */
void
bgp_refresh_begin(struct bgp_channel *c)
{
  struct bgp_proto *p = (void *) c->c.proto;

  if (c->load_state == BFS_LOADING)
  { log(L_WARN "%s: BEGIN-OF-RR received before END-OF-RIB, ignoring", p->p.name); return; }

  if (c->load_state == BFS_REFRESHING)
    rt_refresh_end(&c->c.in_req);

  c->load_state = BFS_REFRESHING;
  rt_refresh_begin(&c->c.in_req);
}

/**
 * bgp_refresh_end - finish incoming enhanced route refresh sequence
 * @c: BGP channel
 *
 * This function is called when an incoming enhanced route refresh sequence is
 * finished by the neighbor, demarcated by the EoRR packet. The function updates
 * the load state and ends the routing table refresh cycle. Routes not received
 * during the sequence are removed by the nest.
 */
void
bgp_refresh_end(struct bgp_channel *c)
{
  struct bgp_proto *p = (void *) c->c.proto;

  if (c->load_state != BFS_REFRESHING)
  { log(L_WARN "%s: END-OF-RR received without prior BEGIN-OF-RR, ignoring", p->p.name); return; }

  c->load_state = BFS_NONE;
  rt_refresh_end(&c->c.in_req);
}


static void
bgp_send_open(struct bgp_conn *conn)
{
  DBG("BGP: Sending open\n");
  conn->sk->rx_hook = bgp_rx;
  conn->sk->tx_hook = bgp_tx;
  tm_stop(conn->connect_timer);
  bgp_prepare_capabilities(conn);
  bgp_schedule_packet(conn, NULL, PKT_OPEN);
  bgp_conn_set_state(conn, BS_OPENSENT);
  bgp_start_timer(conn->hold_timer, conn->bgp->cf->initial_hold_time);
}

static void
bgp_connected(sock *sk)
{
  struct bgp_conn *conn = sk->data;
  struct bgp_proto *p = conn->bgp;

  BGP_TRACE(D_EVENTS, "Connected");
  bgp_send_open(conn);
}

static void
bgp_connect_timeout(timer *t)
{
  struct bgp_conn *conn = t->data;
  struct bgp_proto *p = conn->bgp;

  DBG("BGP: connect_timeout\n");
  if (p->p.proto_state == PS_START)
  {
    bgp_close_conn(conn);
    bgp_connect(p);
  }
  else
    bgp_conn_enter_idle_state(conn);
}

static void
bgp_sock_err(sock *sk, int err)
{
  struct bgp_conn *conn = sk->data;
  struct bgp_proto *p = conn->bgp;

  /*
   * This error hook may be called either asynchronously from main
   * loop, or synchronously from sk_send().  But sk_send() is called
   * only from bgp_tx() and bgp_kick_tx(), which are both called
   * asynchronously from main loop. Moreover, they end if err hook is
   * called. Therefore, we could suppose that it is always called
   * asynchronously.
   */

  bgp_store_error(p, conn, BE_SOCKET, err);

  if (err)
    BGP_TRACE(D_EVENTS, "Connection lost (%M)", err);
  else
    BGP_TRACE(D_EVENTS, "Connection closed");

  if ((conn->state == BS_ESTABLISHED) && p->gr_ready)
    bgp_handle_graceful_restart(p);

  bgp_conn_enter_idle_state(conn);
}

static void
bgp_hold_timeout(timer *t)
{
  struct bgp_conn *conn = t->data;
  struct bgp_proto *p = conn->bgp;

  DBG("BGP: Hold timeout\n");

  /* We are already closing the connection - just do hangup */
  if (conn->state == BS_CLOSE)
  {
    BGP_TRACE(D_EVENTS, "Connection stalled");
    bgp_conn_enter_idle_state(conn);
    return;
  }

  /* If there is something in input queue, we are probably congested
     and perhaps just not processed BGP packets in time. */

  if (sk_rx_ready(conn->sk) > 0)
    bgp_start_timer(conn->hold_timer, 10);
  else if ((conn->state == BS_ESTABLISHED) && p->llgr_ready)
  {
    BGP_TRACE(D_EVENTS, "Hold timer expired");
    bgp_handle_graceful_restart(p);
    bgp_conn_enter_idle_state(conn);
  }
  else
    bgp_error(conn, 4, 0, NULL, 0);
}

static void
bgp_keepalive_timeout(timer *t)
{
  struct bgp_conn *conn = t->data;

  DBG("BGP: Keepalive timer\n");
  bgp_schedule_packet(conn, NULL, PKT_KEEPALIVE);

  /* Kick TX a bit faster */
  if (ev_active(conn->tx_ev))
    ev_run(conn->tx_ev);
}

static void
bgp_setup_conn(struct bgp_proto *p, struct bgp_conn *conn)
{
  conn->sk = NULL;
  conn->bgp = p;

  conn->packets_to_send = 0;
  conn->channels_to_send = 0;
  conn->last_channel = 0;
  conn->last_channel_count = 0;

  conn->connect_timer	= tm_new_init(p->p.pool, bgp_connect_timeout,	 conn, 0, 0);
  conn->hold_timer 	= tm_new_init(p->p.pool, bgp_hold_timeout,	 conn, 0, 0);
  conn->keepalive_timer	= tm_new_init(p->p.pool, bgp_keepalive_timeout, conn, 0, 0);

  conn->tx_ev = ev_new_init(p->p.pool, bgp_kick_tx, conn);
}

static void
bgp_setup_sk(struct bgp_conn *conn, sock *s)
{
  s->data = conn;
  s->err_hook = bgp_sock_err;
  s->fast_rx = 1;
  conn->sk = s;
}

static void
bgp_active(struct bgp_proto *p)
{
  int delay = MAX(1, p->cf->connect_delay_time);
  struct bgp_conn *conn = &p->outgoing_conn;

  BGP_TRACE(D_EVENTS, "Connect delayed by %d seconds", delay);
  bgp_setup_conn(p, conn);
  bgp_conn_set_state(conn, BS_ACTIVE);
  bgp_start_timer(conn->connect_timer, delay);
}

/**
 * bgp_connect - initiate an outgoing connection
 * @p: BGP instance
 *
 * The bgp_connect() function creates a new &bgp_conn and initiates
 * a TCP connection to the peer. The rest of connection setup is governed
 * by the BGP state machine as described in the standard.
 */
static void
bgp_connect(struct bgp_proto *p)	/* Enter Connect state and start establishing connection */
{
  struct bgp_conn *conn = &p->outgoing_conn;
  int hops = p->cf->multihop ? : 1;

  DBG("BGP: Connecting\n");
  sock *s = sk_new(p->p.pool);
  s->type = SK_TCP_ACTIVE;
  s->saddr = p->local_ip;
  s->daddr = p->remote_ip;
  s->dport = p->cf->remote_port;
  s->iface = p->neigh ? p->neigh->iface : NULL;
  s->vrf = p->p.vrf;
  s->ttl = p->cf->ttl_security ? 255 : hops;
  s->rbsize = p->cf->enable_extended_messages ? BGP_RX_BUFFER_EXT_SIZE : BGP_RX_BUFFER_SIZE;
  s->tbsize = p->cf->enable_extended_messages ? BGP_TX_BUFFER_EXT_SIZE : BGP_TX_BUFFER_SIZE;
  s->tos = IP_PREC_INTERNET_CONTROL;
  s->password = p->cf->password;
  s->tx_hook = bgp_connected;
  BGP_TRACE(D_EVENTS, "Connecting to %I%J from local address %I%J",
	    s->daddr, ipa_is_link_local(s->daddr) ? p->cf->iface : NULL,
	    s->saddr, ipa_is_link_local(s->saddr) ? s->iface : NULL);
  bgp_setup_conn(p, conn);
  bgp_setup_sk(conn, s);
  bgp_conn_set_state(conn, BS_CONNECT);

  if (sk_open(s) < 0)
    goto err;

  /* Set minimal receive TTL if needed */
  if (p->cf->ttl_security)
    if (sk_set_min_ttl(s, 256 - hops) < 0)
      goto err;

  DBG("BGP: Waiting for connect success\n");
  bgp_start_timer(conn->connect_timer, p->cf->connect_retry_time);
  return;

err:
  sk_log_error(s, p->p.name);
  bgp_sock_err(s, 0);
  return;
}

static inline int bgp_is_dynamic(struct bgp_proto *p)
{ return ipa_zero(p->remote_ip); }

/**
 * bgp_find_proto - find existing proto for incoming connection
 * @sk: TCP socket
 *
 */
static struct bgp_proto *
bgp_find_proto(sock *sk)
{
  struct bgp_proto *best = NULL;
  struct bgp_proto *p;

  /* sk->iface is valid only if src or dst address is link-local */
  int link = ipa_is_link_local(sk->saddr) || ipa_is_link_local(sk->daddr);

  WALK_LIST(p, proto_list)
    if ((p->p.proto == &proto_bgp) &&
	(ipa_equal(p->remote_ip, sk->daddr) || bgp_is_dynamic(p)) &&
	(!p->cf->remote_range || ipa_in_netX(sk->daddr, p->cf->remote_range)) &&
	(p->p.vrf == sk->vrf) &&
	(p->cf->local_port == sk->sport) &&
	(!link || (p->cf->iface == sk->iface)) &&
	(ipa_zero(p->cf->local_ip) || ipa_equal(p->cf->local_ip, sk->saddr)))
    {
      best = p;

      if (!bgp_is_dynamic(p))
	break;
    }

  return best;
}

/**
 * bgp_incoming_connection - handle an incoming connection
 * @sk: TCP socket
 * @dummy: unused
 *
 * This function serves as a socket hook for accepting of new BGP
 * connections. It searches a BGP instance corresponding to the peer
 * which has connected and if such an instance exists, it creates a
 * &bgp_conn structure, attaches it to the instance and either sends
 * an Open message or (if there already is an active connection) it
 * closes the new connection by sending a Notification message.
 */
static int
bgp_incoming_connection(sock *sk, uint dummy UNUSED)
{
  struct bgp_proto *p;
  int acc, hops;

  DBG("BGP: Incoming connection from %I port %d\n", sk->daddr, sk->dport);
  p = bgp_find_proto(sk);
  if (!p)
  {
    log(L_WARN "BGP: Unexpected connect from unknown address %I%J (port %d)",
	sk->daddr, ipa_is_link_local(sk->daddr) ? sk->iface : NULL, sk->dport);
    rfree(sk);
    return 0;
  }

  /*
   * BIRD should keep multiple incoming connections in OpenSent state (for
   * details RFC 4271 8.2.1 par 3), but it keeps just one. Duplicate incoming
   * connections are rejected istead. The exception is the case where an
   * incoming connection triggers a graceful restart.
   */

  acc = (p->p.proto_state == PS_START || p->p.proto_state == PS_UP) &&
    (p->start_state >= BSS_CONNECT) && (!p->incoming_conn.sk);

  if (p->conn && (p->conn->state == BS_ESTABLISHED) && p->gr_ready)
  {
    bgp_store_error(p, NULL, BE_MISC, BEM_GRACEFUL_RESTART);
    bgp_handle_graceful_restart(p);
    bgp_conn_enter_idle_state(p->conn);
    acc = 1;

    /* There might be separate incoming connection in OpenSent state */
    if (p->incoming_conn.state > BS_ACTIVE)
      bgp_close_conn(&p->incoming_conn);
  }

  BGP_TRACE(D_EVENTS, "Incoming connection from %I%J (port %d) %s",
	    sk->daddr, ipa_is_link_local(sk->daddr) ? sk->iface : NULL,
	    sk->dport, acc ? "accepted" : "rejected");

  if (!acc)
  {
    rfree(sk);
    return 0;
  }

  hops = p->cf->multihop ? : 1;

  if (sk_set_ttl(sk, p->cf->ttl_security ? 255 : hops) < 0)
    goto err;

  if (p->cf->ttl_security)
    if (sk_set_min_ttl(sk, 256 - hops) < 0)
      goto err;

  if (p->cf->enable_extended_messages)
  {
    sk->rbsize = BGP_RX_BUFFER_EXT_SIZE;
    sk->tbsize = BGP_TX_BUFFER_EXT_SIZE;
    sk_reallocate(sk);
  }

  /* For dynamic BGP, spawn new instance and postpone the socket */
  if (bgp_is_dynamic(p))
  {
    p = bgp_spawn(p, sk->daddr);
    p->postponed_sk = sk;
    rmove(sk, p->p.pool);
    return 0;
  }

  rmove(sk, p->p.pool);
  bgp_setup_conn(p, &p->incoming_conn);
  bgp_setup_sk(&p->incoming_conn, sk);
  bgp_send_open(&p->incoming_conn);
  return 0;

err:
  sk_log_error(sk, p->p.name);
  log(L_ERR "%s: Incoming connection aborted", p->p.name);
  rfree(sk);
  return 0;
}

static void
bgp_listen_sock_err(sock *sk UNUSED, int err)
{
  if (err == ECONNABORTED)
    log(L_WARN "BGP: Incoming connection aborted");
  else
    log(L_ERR "BGP: Error on listening socket: %M", err);
}

static void
bgp_start_neighbor(struct bgp_proto *p)
{
  /* Called only for single-hop BGP sessions */

  if (ipa_zero(p->local_ip))
    p->local_ip = p->neigh->ifa->ip;

  if (ipa_is_link_local(p->local_ip))
    p->link_addr = p->local_ip;
  else if (p->neigh->iface->llv6)
    p->link_addr = p->neigh->iface->llv6->ip;

  bgp_initiate(p);
}

static void
bgp_neigh_notify(neighbor *n)
{
  struct bgp_proto *p = (struct bgp_proto *) n->proto;
  int ps = p->p.proto_state;

  if (n != p->neigh)
    return;

  if ((ps == PS_DOWN) || (ps == PS_STOP))
    return;

  int prepare = (ps == PS_START) && (p->start_state == BSS_PREPARE);

  if (n->scope <= 0)
  {
    if (!prepare)
    {
      BGP_TRACE(D_EVENTS, "Neighbor lost");
      bgp_store_error(p, NULL, BE_MISC, BEM_NEIGHBOR_LOST);
      /* Perhaps also run bgp_update_startup_delay(p)? */
      bgp_stop(p, 0, NULL, 0);
    }
  }
  else if (p->cf->check_link && !(n->iface->flags & IF_LINK_UP))
  {
    if (!prepare)
    {
      BGP_TRACE(D_EVENTS, "Link down");
      bgp_store_error(p, NULL, BE_MISC, BEM_LINK_DOWN);
      if (ps == PS_UP)
	bgp_update_startup_delay(p);
      bgp_stop(p, 0, NULL, 0);
    }
  }
  else
  {
    if (prepare)
    {
      BGP_TRACE(D_EVENTS, "Neighbor ready");
      bgp_start_neighbor(p);
    }
  }
}

static void
bgp_bfd_notify(struct bfd_request *req)
{
  struct bgp_proto *p = req->data;
  int ps = p->p.proto_state;

  if (req->down && ((ps == PS_START) || (ps == PS_UP)))
  {
    BGP_TRACE(D_EVENTS, "BFD session down");
    bgp_store_error(p, NULL, BE_MISC, BEM_BFD_DOWN);

    if (req->opts.mode == BGP_BFD_GRACEFUL)
    {
      /* Trigger graceful restart */
      if (p->conn && (p->conn->state == BS_ESTABLISHED) && p->gr_ready)
	bgp_handle_graceful_restart(p);

      if (p->incoming_conn.state > BS_IDLE)
	bgp_conn_enter_idle_state(&p->incoming_conn);

      if (p->outgoing_conn.state > BS_IDLE)
	bgp_conn_enter_idle_state(&p->outgoing_conn);
    }
    else
    {
      /* Trigger session down */
      if (ps == PS_UP)
	bgp_update_startup_delay(p);
      bgp_stop(p, 0, NULL, 0);
    }
  }
}

static void
bgp_update_bfd(struct bgp_proto *p, const struct bfd_options *bfd)
{
  if (bfd && p->bfd_req)
    bfd_update_request(p->bfd_req, bfd);

  if (bfd && !p->bfd_req && !bgp_is_dynamic(p))
    p->bfd_req = bfd_request_session(p->p.pool, p->remote_ip, p->local_ip,
				     p->cf->multihop ? NULL : p->neigh->iface,
				     p->p.vrf, bgp_bfd_notify, p, bfd);

  if (!bfd && p->bfd_req)
  {
    rfree(p->bfd_req);
    p->bfd_req = NULL;
  }
}

static void
bgp_reload_routes(struct channel *C)
{
  struct bgp_proto *p = (void *) C->proto;
  struct bgp_channel *c = (void *) C;

  ASSERT(p->conn && p->route_refresh);
  bgp_schedule_packet(p->conn, c, PKT_ROUTE_REFRESH);
}

static void
bgp_feed_begin(struct channel *C, int initial)
{
  struct bgp_proto *p = (void *) C->proto;
  struct bgp_channel *c = (void *) C;

  /* This should not happen */
  if (!p->conn)
    return;

  if (initial && p->cf->gr_mode)
    c->feed_state = BFS_LOADING;

  if (!initial && C->out_table)
  {
    c->feed_out_table = 1;
    return;
  }

  /* It is refeed and both sides support enhanced route refresh */
  if (!initial && p->enhanced_refresh)
  {
    /* BoRR must not be sent before End-of-RIB */
    if (c->feed_state == BFS_LOADING || c->feed_state == BFS_LOADED)
      return;

    c->feed_state = BFS_REFRESHING;
    bgp_schedule_packet(p->conn, c, PKT_BEGIN_REFRESH);
  }
}

static void
bgp_feed_end(struct channel *C)
{
  struct bgp_proto *p = (void *) C->proto;
  struct bgp_channel *c = (void *) C;

  if (c->feed_out_table)
  {
    c->feed_out_table = 0;
    return;
  }

  /* This should not happen */
  if (!p->conn)
    return;

  /* Non-demarcated feed ended, nothing to do */
  if (c->feed_state == BFS_NONE)
    return;

  /* Schedule End-of-RIB packet */
  if (c->feed_state == BFS_LOADING)
    c->feed_state = BFS_LOADED;

  /* Schedule EoRR packet */
  if (c->feed_state == BFS_REFRESHING)
    c->feed_state = BFS_REFRESHED;

  /* Kick TX hook */
  bgp_schedule_packet(p->conn, c, PKT_UPDATE);
}


static void
bgp_start_locked(struct object_lock *lock)
{
  struct bgp_proto *p = lock->data;
  const struct bgp_config *cf = p->cf;

  if (p->p.proto_state != PS_START)
  {
    DBG("BGP: Got lock in different state %d\n", p->p.proto_state);
    return;
  }

  DBG("BGP: Got lock\n");

  if (cf->multihop || bgp_is_dynamic(p))
  {
    /* Multi-hop sessions do not use neighbor entries */
    bgp_initiate(p);
    return;
  }

  neighbor *n = neigh_find(&p->p, p->remote_ip, cf->iface, NEF_STICKY);
  if (!n)
  {
    log(L_ERR "%s: Invalid remote address %I%J", p->p.name, p->remote_ip, cf->iface);
    /* As we do not start yet, we can just disable protocol */
    p->p.disabled = 1;
    bgp_store_error(p, NULL, BE_MISC, BEM_INVALID_NEXT_HOP);
    proto_notify_state(&p->p, PS_DOWN);
    return;
  }

  p->neigh = n;

  if (n->scope <= 0)
    BGP_TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", p->remote_ip, cf->iface);
  else if (p->cf->check_link && !(n->iface->flags & IF_LINK_UP))
    BGP_TRACE(D_EVENTS, "Waiting for link on %s", n->iface->name);
  else
    bgp_start_neighbor(p);
}

static int
bgp_start(struct proto *P)
{
  struct bgp_proto *p = (struct bgp_proto *) P;
  const struct bgp_config *cf = p->cf;

  p->local_ip = cf->local_ip;
  p->local_as = cf->local_as;
  p->remote_as = cf->remote_as;
  p->public_as = cf->local_as;

  /* For dynamic BGP childs, remote_ip is already set */
  if (ipa_nonzero(cf->remote_ip))
    p->remote_ip = cf->remote_ip;

  /* Confederation ID is used for truly external peers */
  if (p->cf->confederation && !p->is_interior)
    p->public_as = cf->confederation;

  p->passive = cf->passive || bgp_is_dynamic(p);

  p->start_state = BSS_PREPARE;
  p->outgoing_conn.state = BS_IDLE;
  p->incoming_conn.state = BS_IDLE;
  p->neigh = NULL;
  p->bfd_req = NULL;
  p->postponed_sk = NULL;
  p->gr_ready = 0;
  p->gr_active_num = 0;

  /* Reset some stats */
  p->stats.rx_messages = p->stats.tx_messages = 0;
  p->stats.rx_updates = p->stats.tx_updates = 0;
  p->stats.rx_bytes = p->stats.tx_bytes = 0;
  p->last_rx_update = 0;

  p->event = ev_new_init(p->p.pool, bgp_decision, p);
  p->uncork_ev = ev_new_init(p->p.pool, bgp_uncork, p);

  p->startup_timer = tm_new_init(p->p.pool, bgp_startup_timeout, p, 0, 0);
  p->gr_timer = tm_new_init(p->p.pool, bgp_graceful_restart_timeout, p, 0, 0);

  p->local_id = proto_get_router_id(P->cf);
  if (p->rr_client)
    p->rr_cluster_id = p->cf->rr_cluster_id ? p->cf->rr_cluster_id : p->local_id;

  p->remote_id = 0;
  p->link_addr = IPA_NONE;

  /* Lock all channels when in GR recovery mode */
  if (p->p.gr_recovery && p->cf->gr_mode)
  {
    struct bgp_channel *c;
    WALK_LIST(c, p->p.channels)
      channel_graceful_restart_lock(&c->c);
  }

  /*
   * Before attempting to create the connection, we need to lock the port,
   * so that we are the only instance attempting to talk with that neighbor.
   */
  struct object_lock *lock;
  lock = p->lock = olock_new(P->pool);
  lock->addr = p->remote_ip;
  lock->port = p->cf->remote_port;
  lock->iface = p->cf->iface;
  lock->vrf = p->cf->iface ? NULL : p->p.vrf;
  lock->type = OBJLOCK_TCP;
  lock->hook = bgp_start_locked;
  lock->data = p;

  /* For dynamic BGP, we use inst 1 to avoid collisions with regular BGP */
  if (bgp_is_dynamic(p))
  {
    lock->addr = net_prefix(p->cf->remote_range);
    lock->inst = 1;
  }

  olock_acquire(lock);

  return PS_START;
}

extern int proto_restart;

static int
bgp_shutdown(struct proto *P)
{
  struct bgp_proto *p = (struct bgp_proto *) P;
  int subcode = 0;

  char *message = NULL;
  byte *data = NULL;
  uint len = 0;

  BGP_TRACE(D_EVENTS, "Shutdown requested");

  switch (P->down_code)
  {
  case PDC_CF_REMOVE:
  case PDC_CF_DISABLE:
    subcode = 3; // Errcode 6, 3 - peer de-configured
    break;

  case PDC_CF_RESTART:
    subcode = 6; // Errcode 6, 6 - other configuration change
    break;

  case PDC_CMD_DISABLE:
  case PDC_CMD_SHUTDOWN:
  shutdown:
    subcode = 2; // Errcode 6, 2 - administrative shutdown
    message = P->message;
    break;

  case PDC_CMD_RESTART:
    subcode = 4; // Errcode 6, 4 - administrative reset
    message = P->message;
    break;

  case PDC_CMD_GR_DOWN:
    if ((p->cf->gr_mode != BGP_GR_ABLE) &&
	(p->cf->llgr_mode != BGP_LLGR_ABLE))
      goto shutdown;

    subcode = -1; // Do not send NOTIFICATION, just close the connection
    break;

  case PDC_RX_LIMIT_HIT:
  case PDC_IN_LIMIT_HIT:
    subcode = 1; // Errcode 6, 1 - max number of prefixes reached
    /* log message for compatibility */
    log(L_WARN "%s: Route limit exceeded, shutting down", p->p.name);
    goto limit;

  case PDC_OUT_LIMIT_HIT:
    subcode = proto_restart ? 4 : 2; // Administrative reset or shutdown

  limit:
    bgp_store_error(p, NULL, BE_AUTO_DOWN, BEA_ROUTE_LIMIT_EXCEEDED);
    if (proto_restart)
      bgp_update_startup_delay(p);
    else
      p->startup_delay = 0;
    goto done;
  }

  bgp_store_error(p, NULL, BE_MAN_DOWN, 0);
  p->startup_delay = 0;

  /* RFC 8203 - shutdown communication */
  if (message)
  {
    uint msg_len = strlen(message);
    msg_len = MIN(msg_len, 255);

    /* Buffer will be freed automatically by protocol shutdown */
    data = mb_alloc(p->p.pool, msg_len + 1);
    len = msg_len + 1;

    data[0] = msg_len;
    memcpy(data+1, message, msg_len);
  }

done:
  bgp_stop(p, subcode, data, len);
  return p->p.proto_state;
}

struct rte_owner_class bgp_rte_owner_class = {
  .get_route_info = 	bgp_get_route_info,
  .rte_better =		bgp_rte_better,
  .rte_mergable =	bgp_rte_mergable,
  .rte_igp_metric =	bgp_rte_igp_metric,
};

static struct proto *
bgp_init(struct proto_config *CF)
{
  struct proto *P = proto_new(CF);
  struct bgp_proto *p = (struct bgp_proto *) P;
  struct bgp_config *cf = (struct bgp_config *) CF;

  P->rt_notify = bgp_rt_notify;
  P->preexport = bgp_preexport;
  P->neigh_notify = bgp_neigh_notify;
  P->reload_routes = bgp_reload_routes;
  P->feed_begin = bgp_feed_begin;
  P->feed_end = bgp_feed_end;

  P->sources.class = &bgp_rte_owner_class;
  P->sources.rte_recalculate = cf->deterministic_med ? bgp_rte_recalculate : NULL;

  p->cf = cf;
  p->is_internal = (cf->local_as == cf->remote_as);
  p->is_interior = p->is_internal || cf->confederation_member;
  p->rs_client = cf->rs_client;
  p->rr_client = cf->rr_client;

  p->ipv4 = ipa_nonzero(cf->remote_ip) ?
    ipa_is_ip4(cf->remote_ip) :
    (cf->remote_range && (cf->remote_range->type == NET_IP4));

  p->remote_ip = cf->remote_ip;
  p->remote_as = cf->remote_as;

  /* Hack: We use cf->remote_ip just to pass remote_ip from bgp_spawn() */
  if (cf->c.parent)
    cf->remote_ip = IPA_NONE;

  /* Add all channels */
  struct bgp_channel_config *cc;
  WALK_LIST(cc, CF->channels)
    proto_add_channel(P, &cc->c);

  return P;
}

static void
bgp_channel_init(struct channel *C, struct channel_config *CF)
{
  struct bgp_channel *c = (void *) C;
  struct bgp_channel_config *cf = (void *) CF;

  c->cf = cf;
  c->afi = cf->afi;
  c->desc = cf->desc;

  if (cf->igp_table_ip4)
    c->igp_table_ip4 = cf->igp_table_ip4->table;

  if (cf->igp_table_ip6)
    c->igp_table_ip6 = cf->igp_table_ip6->table;

  if (cf->base_table)
    c->base_table = cf->base_table->table;
}

static int
bgp_channel_start(struct channel *C)
{
  struct bgp_proto *p = (void *) C->proto;
  struct bgp_channel *c = (void *) C;
  ip_addr src = p->local_ip;

  if (c->igp_table_ip4)
    rt_lock_table(c->igp_table_ip4);

  if (c->igp_table_ip6)
    rt_lock_table(c->igp_table_ip6);

  if (c->base_table)
  {
    rt_lock_table(c->base_table);
    rt_flowspec_link(c->base_table, c->c.table);
  }

  c->pool = p->p.pool; // XXXX

  if (c->cf->import_table)
    channel_setup_in_table(C);

  if (c->cf->export_table)
    bgp_setup_out_table(c);

  bgp_init_pending_tx(c);

  c->stale_timer = tm_new_init(c->pool, bgp_long_lived_stale_timeout, c, 0, 0);

  c->next_hop_addr = c->cf->next_hop_addr;
  c->link_addr = IPA_NONE;
  c->packets_to_send = 0;

  /* Try to use source address as next hop address */
  if (ipa_zero(c->next_hop_addr))
  {
    if (bgp_channel_is_ipv4(c) && (ipa_is_ip4(src) || c->ext_next_hop))
      c->next_hop_addr = src;

    if (bgp_channel_is_ipv6(c) && (ipa_is_ip6(src) || c->ext_next_hop))
      c->next_hop_addr = src;
  }

  /* Use preferred addresses associated with interface / source address */
  if (ipa_zero(c->next_hop_addr))
  {
    /* We know the iface for single-hop, we make lookup for multihop */
    struct neighbor *nbr = p->neigh ?: neigh_find(&p->p, src, NULL, 0);
    struct iface *iface = nbr ? nbr->iface : NULL;

    if (bgp_channel_is_ipv4(c) && iface && iface->addr4)
      c->next_hop_addr = iface->addr4->ip;

    if (bgp_channel_is_ipv6(c) && iface && iface->addr6)
      c->next_hop_addr = iface->addr6->ip;
  }

  /* Exit if no feasible next hop address is found */
  if (ipa_zero(c->next_hop_addr))
  {
    log(L_WARN "%s: Missing next hop address", p->p.name);
    return 0;
  }

  /* Set link-local address for IPv6 single-hop BGP */
  if (ipa_is_ip6(c->next_hop_addr) && p->neigh)
  {
    c->link_addr = p->link_addr;

    if (ipa_zero(c->link_addr))
      log(L_WARN "%s: Missing link-local address", p->p.name);
  }

  /* Link local address is already in c->link_addr */
  if (ipa_is_link_local(c->next_hop_addr))
    c->next_hop_addr = IPA_NONE;

  return 0; /* XXXX: Currently undefined */
}

static void
bgp_channel_shutdown(struct channel *C)
{
  struct bgp_channel *c = (void *) C;

  c->next_hop_addr = IPA_NONE;
  c->link_addr = IPA_NONE;
  c->packets_to_send = 0;
}

static void
bgp_channel_cleanup(struct channel *C)
{
  struct bgp_channel *c = (void *) C;

  if (c->igp_table_ip4)
    rt_unlock_table(c->igp_table_ip4);

  if (c->igp_table_ip6)
    rt_unlock_table(c->igp_table_ip6);

  if (c->base_table)
  {
    rt_flowspec_unlink(c->base_table, c->c.table);
    rt_unlock_table(c->base_table);
  }

  c->index = 0;

  /* Cleanup rest of bgp_channel starting at pool field */
  memset(&(c->pool), 0, sizeof(struct bgp_channel) - OFFSETOF(struct bgp_channel, pool));
}

static inline struct bgp_channel_config *
bgp_find_channel_config(struct bgp_config *cf, u32 afi)
{
  struct bgp_channel_config *cc;

  WALK_LIST(cc, cf->c.channels)
    if (cc->afi == afi)
      return cc;

  return NULL;
}

struct rtable_config *
bgp_default_igp_table(struct bgp_config *cf, struct bgp_channel_config *cc, u32 type)
{
  struct bgp_channel_config *cc2;
  struct rtable_config *tab;

  /* First, try table connected by the channel */
  if (cc->c.table->addr_type == type)
    return cc->c.table;

  /* Find paired channel with the same SAFI but the other AFI */
  u32 afi2 = cc->afi ^ 0x30000;
  cc2 = bgp_find_channel_config(cf, afi2);

  /* Second, try IGP table configured in the paired channel */
  if (cc2 && (tab = (type == NET_IP4) ? cc2->igp_table_ip4 : cc2->igp_table_ip6))
    return tab;

  /* Third, try table connected by the paired channel */
  if (cc2 && (cc2->c.table->addr_type == type))
    return cc2->c.table;

  /* Last, try default table of given type */
  if (tab = rt_get_default_table(cf->c.global, type))
    return tab;

  cf_error("Undefined IGP table");
}

static struct rtable_config *
bgp_default_base_table(struct bgp_config *cf, struct bgp_channel_config *cc)
{
  /* Expected table type */
  u32 type = (cc->afi == BGP_AF_FLOW4) ? NET_IP4 : NET_IP6;

  /* First, try appropriate IP channel */
  u32 afi2 = BGP_AF(BGP_AFI(cc->afi), BGP_SAFI_UNICAST);
  struct bgp_channel_config *cc2 = bgp_find_channel_config(cf, afi2);
  if (cc2 && (cc2->c.table->addr_type == type))
    return cc2->c.table;

  /* Last, try default table of given type */
  struct rtable_config *tab = rt_get_default_table(cf->c.global, type);
  if (tab)
    return tab;

  cf_error("Undefined base table");
}

void
bgp_postconfig(struct proto_config *CF)
{
  struct bgp_config *cf = (void *) CF;

  /* Do not check templates at all */
  if (cf->c.class == SYM_TEMPLATE)
    return;


  /* Handle undefined remote_as, zero should mean unspecified external */
  if (!cf->remote_as && (cf->peer_type == BGP_PT_INTERNAL))
    cf->remote_as = cf->local_as;

  int internal = (cf->local_as == cf->remote_as);
  int interior = internal || cf->confederation_member;

  /* EBGP direct by default, IBGP multihop by default */
  if (cf->multihop < 0)
    cf->multihop = internal ? 64 : 0;

  /* LLGR mode default based on GR mode */
  if (cf->llgr_mode < 0)
    cf->llgr_mode = cf->gr_mode ? BGP_LLGR_AWARE : 0;

  /* Link check for single-hop BGP by default */
  if (cf->check_link < 0)
    cf->check_link = !cf->multihop;


  if (!cf->local_as)
    cf_error("Local AS number must be set");

  if (ipa_zero(cf->remote_ip) && !cf->remote_range)
    cf_error("Neighbor must be configured");

  if (ipa_zero(cf->local_ip) && cf->strict_bind)
    cf_error("Local address must be configured for strict bind");

  if (!cf->remote_as && !cf->peer_type)
    cf_error("Remote AS number (or peer type) must be set");

  if ((cf->peer_type == BGP_PT_INTERNAL) && !internal)
    cf_error("IBGP cannot have different ASNs");

  if ((cf->peer_type == BGP_PT_EXTERNAL) &&  internal)
    cf_error("EBGP cannot have the same ASNs");

  if (!cf->iface && (ipa_is_link_local(cf->local_ip) ||
		     ipa_is_link_local(cf->remote_ip)))
    cf_error("Link-local addresses require defined interface");

  if (!(cf->capabilities && cf->enable_as4) && (cf->remote_as > 0xFFFF))
    cf_error("Neighbor AS number out of range (AS4 not available)");

  if (!internal && cf->rr_client)
    cf_error("Only internal neighbor can be RR client");

  if (internal && cf->rs_client)
    cf_error("Only external neighbor can be RS client");

  if (internal && (cf->local_role != BGP_ROLE_UNDEFINED))
    cf_error("Local role cannot be set on IBGP sessions");

  if (interior && (cf->local_role != BGP_ROLE_UNDEFINED))
    log(L_WARN "BGP roles are not recommended to be used within AS confederations");

  if (cf->require_roles && (cf->local_role == BGP_ROLE_UNDEFINED))
    cf_error("Local role must be set if roles are required");

  if (!cf->confederation && cf->confederation_member)
    cf_error("Confederation ID must be set for member sessions");

  if (cf->multihop && (ipa_is_link_local(cf->local_ip) ||
		       ipa_is_link_local(cf->remote_ip)))
    cf_error("Multihop BGP cannot be used with link-local addresses");

  if (cf->multihop && cf->iface)
    cf_error("Multihop BGP cannot be bound to interface");

  if (cf->multihop && cf->check_link)
    cf_error("Multihop BGP cannot depend on link state");

  if (cf->multihop && cf->bfd && ipa_zero(cf->local_ip))
    cf_error("Multihop BGP with BFD requires specified local address");

  if (!cf->gr_mode && cf->llgr_mode)
    cf_error("Long-lived graceful restart requires basic graceful restart");

  if (internal && cf->enforce_first_as)
    cf_error("Enforce first AS check is requires EBGP sessions");


  struct bgp_channel_config *cc;
  WALK_LIST(cc, CF->channels)
  {
    /* Handle undefined import filter */
    if (cc->c.in_filter == FILTER_UNDEF)
      if (interior)
	cc->c.in_filter = FILTER_ACCEPT;
      else
	cf_error("EBGP requires explicit import policy");

    /* Handle undefined export filter */
    if (cc->c.out_filter == FILTER_UNDEF)
      if (interior)
	cc->c.out_filter = FILTER_REJECT;
      else
	cf_error("EBGP requires explicit export policy");

    /* Disable after error incompatible with restart limit action */
    if ((cc->c.in_limit.action == PLA_RESTART) && cf->disable_after_error)
      cc->c.in_limit.action = PLA_DISABLE;

    /* Different default based on rr_client, rs_client */
    if (cc->next_hop_keep == 0xff)
      cc->next_hop_keep = cf->rr_client ? NH_IBGP : (cf->rs_client ? NH_ALL : NH_NO);

    /* Different default for gw_mode */
    if (!cc->gw_mode)
      cc->gw_mode = cf->multihop ? GW_RECURSIVE : GW_DIRECT;

    /* Defaults based on proto config */
    if (cc->gr_able == 0xff)
      cc->gr_able = (cf->gr_mode == BGP_GR_ABLE);

    if (cc->llgr_able == 0xff)
      cc->llgr_able = (cf->llgr_mode == BGP_LLGR_ABLE);

    if (cc->llgr_time == ~0U)
      cc->llgr_time = cf->llgr_time;

    /* AIGP enabled by default on interior sessions */
    if (cc->aigp == 0xff)
      cc->aigp = interior;

    /* Default values of IGP tables */
    if ((cc->gw_mode == GW_RECURSIVE) && !cc->desc->no_igp)
    {
      if (!cc->igp_table_ip4 && (bgp_cc_is_ipv4(cc) || cc->ext_next_hop))
	cc->igp_table_ip4 = bgp_default_igp_table(cf, cc, NET_IP4);

      if (!cc->igp_table_ip6 && (bgp_cc_is_ipv6(cc) || cc->ext_next_hop))
	cc->igp_table_ip6 = bgp_default_igp_table(cf, cc, NET_IP6);

      if (cc->igp_table_ip4 && bgp_cc_is_ipv6(cc) && !cc->ext_next_hop)
	cf_error("Mismatched IGP table type");

      if (cc->igp_table_ip6 && bgp_cc_is_ipv4(cc) && !cc->ext_next_hop)
	cf_error("Mismatched IGP table type");
    }

    /* Default value of base table */
    if ((BGP_SAFI(cc->afi) == BGP_SAFI_FLOW) && cc->validate && !cc->base_table)
      cc->base_table = bgp_default_base_table(cf, cc);

    if (cc->base_table && !cc->base_table->trie_used)
      cf_error("Flowspec validation requires base table (%s) with trie",
	       cc->base_table->name);

    if (cf->multihop && (cc->gw_mode == GW_DIRECT))
      cf_error("Multihop BGP cannot use direct gateway mode");

    if ((cc->gw_mode == GW_RECURSIVE) && cc->c.table->sorted)
      cf_error("BGP in recursive mode prohibits sorted table");

    if (cf->deterministic_med && cc->c.table->sorted)
      cf_error("BGP with deterministic MED prohibits sorted table");

    if (cc->secondary && !cc->c.table->sorted)
      cf_error("BGP with secondary option requires sorted table");
  }
}

static int
bgp_reconfigure(struct proto *P, struct proto_config *CF)
{
  struct bgp_proto *p = (void *) P;
  const struct bgp_config *new = (void *) CF;
  const struct bgp_config *old = p->cf;

  if (proto_get_router_id(CF) != p->local_id)
    return 0;

  int same = !memcmp(((byte *) old) + sizeof(struct proto_config),
		     ((byte *) new) + sizeof(struct proto_config),
		     // password item is last and must be checked separately
		     OFFSETOF(struct bgp_config, password) - sizeof(struct proto_config))
    && !bstrcmp(old->password, new->password)
    && ((!old->remote_range && !new->remote_range)
	|| (old->remote_range && new->remote_range && net_equal(old->remote_range, new->remote_range)))
    && !bstrcmp(old->dynamic_name, new->dynamic_name)
    && (old->dynamic_name_digits == new->dynamic_name_digits);

  /* FIXME: Move channel reconfiguration to generic protocol code ? */
  struct channel *C, *C2;
  struct bgp_channel_config *cc;

  WALK_LIST(C, p->p.channels)
    C->stale = 1;

  WALK_LIST(cc, new->c.channels)
  {
    C = (struct channel *) bgp_find_channel(p, cc->afi);
    same = proto_configure_channel(P, &C, &cc->c) && same;

    if (C)
      C->stale = 0;
  }

  WALK_LIST_DELSAFE(C, C2, p->p.channels)
    if (C->stale)
      same = proto_configure_channel(P, &C, NULL) && same;


  if (same && (p->start_state > BSS_PREPARE))
    bgp_update_bfd(p, new->bfd);

  /* We should update our copy of configuration ptr as old configuration will be freed */
  if (same)
    p->cf = new;

  /* Reset name counter */
  p->dynamic_name_counter = 0;

  return same;
}

#define TABLE(cf, NAME) ((cf)->NAME ? (cf)->NAME->table : NULL )

static int
bgp_channel_reconfigure(struct channel *C, struct channel_config *CC, int *import_changed, int *export_changed)
{
  struct bgp_proto *p = (void *) C->proto;
  struct bgp_channel *c = (void *) C;
  struct bgp_channel_config *new = (void *) CC;
  struct bgp_channel_config *old = c->cf;

  if ((new->secondary != old->secondary) ||
      (new->validate != old->validate) ||
      (new->gr_able != old->gr_able) ||
      (new->llgr_able != old->llgr_able) ||
      (new->llgr_time != old->llgr_time) ||
      (new->ext_next_hop != old->ext_next_hop) ||
      (new->add_path != old->add_path) ||
      (new->import_table != old->import_table) ||
      (new->export_table != old->export_table) ||
      (TABLE(new, igp_table_ip4) != TABLE(old, igp_table_ip4)) ||
      (TABLE(new, igp_table_ip6) != TABLE(old, igp_table_ip6)) ||
      (TABLE(new, base_table) != TABLE(old, base_table)))
    return 0;

  if (new->mandatory && !old->mandatory && (C->channel_state != CS_UP))
    return 0;

  if ((new->gw_mode != old->gw_mode) ||
      (new->aigp != old->aigp) ||
      (new->cost != old->cost))
  {
    /* import_changed itself does not force ROUTE_REFRESH when import_table is active */
    if ((c->c.in_keep & RIK_PREFILTER) && (c->c.channel_state == CS_UP))
      bgp_schedule_packet(p->conn, c, PKT_ROUTE_REFRESH);

    *import_changed = 1;
  }

  if (!ipa_equal(new->next_hop_addr, old->next_hop_addr) ||
      (new->next_hop_self != old->next_hop_self) ||
      (new->next_hop_keep != old->next_hop_keep) ||
      (new->aigp != old->aigp) ||
      (new->aigp_originate != old->aigp_originate))
    *export_changed = 1;

  c->cf = new;
  return 1;
}

static void
bgp_copy_config(struct proto_config *dest, struct proto_config *src)
{
  struct bgp_config *d = (void *) dest;
  struct bgp_config *s = (void *) src;

  /* Copy BFD options */
  if (s->bfd)
  {
    struct bfd_options *opts = cfg_alloc(sizeof(struct bfd_options));
    memcpy(opts, s->bfd, sizeof(struct bfd_options));
    d->bfd = opts;
  }
}


/**
 * bgp_error - report a protocol error
 * @c: connection
 * @code: error code (according to the RFC)
 * @subcode: error sub-code
 * @data: data to be passed in the Notification message
 * @len: length of the data
 *
 * bgp_error() sends a notification packet to tell the other side that a protocol
 * error has occurred (including the data considered erroneous if possible) and
 * closes the connection.
 */
void
bgp_error(struct bgp_conn *c, uint code, uint subcode, byte *data, int len)
{
  struct bgp_proto *p = c->bgp;

  if (c->state == BS_CLOSE)
    return;

  bgp_log_error(p, BE_BGP_TX, "Error", code, subcode, data, ABS(len));
  bgp_store_error(p, c, BE_BGP_TX, (code << 16) | subcode);
  bgp_conn_enter_close_state(c);

  c->notify_code = code;
  c->notify_subcode = subcode;
  c->notify_data = data;
  c->notify_size = (len > 0) ? len : 0;
  bgp_schedule_packet(c, NULL, PKT_NOTIFICATION);

  if (code != 6)
  {
    bgp_update_startup_delay(p);
    bgp_stop(p, 0, NULL, 0);
  }
}

/**
 * bgp_store_error - store last error for status report
 * @p: BGP instance
 * @c: connection
 * @class: error class (BE_xxx constants)
 * @code: error code (class specific)
 *
 * bgp_store_error() decides whether given error is interesting enough
 * and store that error to last_error variables of @p
 */
void
bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code)
{
  /* During PS_UP, we ignore errors on secondary connection */
  if ((p->p.proto_state == PS_UP) && c && (c != p->conn))
    return;

  /* During PS_STOP, we ignore any errors, as we want to report
   * the error that caused transition to PS_STOP
   */
  if (p->p.proto_state == PS_STOP)
    return;

  p->last_error_class = class;
  p->last_error_code = code;
}

static char *bgp_state_names[] = { "Idle", "Connect", "Active", "OpenSent", "OpenConfirm", "Established", "Close" };
static char *bgp_err_classes[] = { "", "Error: ", "Socket: ", "Received: ", "BGP Error: ", "Automatic shutdown: ", ""};
static char *bgp_misc_errors[] = { "", "Neighbor lost", "Invalid next hop", "Kernel MD5 auth failed", "No listening socket", "Link down", "BFD session down", "Graceful restart"};
static char *bgp_auto_errors[] = { "", "Route limit exceeded"};
static char *bgp_gr_states[] = { "None", "Regular", "Long-lived"};

static const char *
bgp_last_errmsg(struct bgp_proto *p)
{
  switch (p->last_error_class)
  {
  case BE_MISC:
    return bgp_misc_errors[p->last_error_code];
  case BE_SOCKET:
    return (p->last_error_code == 0) ? "Connection closed" : strerror(p->last_error_code);
  case BE_BGP_RX:
  case BE_BGP_TX:
    return bgp_error_dsc(p->last_error_code >> 16, p->last_error_code & 0xFF);
  case BE_AUTO_DOWN:
    return bgp_auto_errors[p->last_error_code];
  default:
    return "";
  }
}

static const char *
bgp_state_dsc(struct bgp_proto *p)
{
  if (p->p.proto_state == PS_DOWN)
    return "Down";

  int state = MAX(p->incoming_conn.state, p->outgoing_conn.state);
  if ((state == BS_IDLE) && (p->start_state >= BSS_CONNECT) && p->passive)
    return "Passive";

  return bgp_state_names[state];
}

static void
bgp_get_status(struct proto *P, byte *buf)
{
  struct bgp_proto *p = (struct bgp_proto *) P;

  const char *err1 = bgp_err_classes[p->last_error_class];
  const char *err2 = bgp_last_errmsg(p);

  if (P->proto_state == PS_DOWN)
    bsprintf(buf, "%s%s", err1, err2);
  else
    bsprintf(buf, "%-14s%s%s", bgp_state_dsc(p), err1, err2);
}

static void
bgp_show_afis(int code, char *s, u32 *afis, uint count)
{
  buffer b;
  LOG_BUFFER_INIT(b);

  buffer_puts(&b, s);

  for (u32 *af = afis; af < (afis + count); af++)
  {
    const struct bgp_af_desc *desc = bgp_get_af_desc(*af);
    if (desc)
      buffer_print(&b, " %s", desc->name);
    else
      buffer_print(&b, " <%u/%u>", BGP_AFI(*af), BGP_SAFI(*af));
  }

  if (b.pos == b.end)
    strcpy(b.end - 32, " ... <too long>");

  cli_msg(code, b.start);
}

static const char *
bgp_format_role_name(u8 role)
{
  static const char *bgp_role_names[] = { "provider", "rs_server", "rs_client", "customer", "peer" };
  if (role == BGP_ROLE_UNDEFINED) return "undefined";
  if (role < ARRAY_SIZE(bgp_role_names)) return bgp_role_names[role];
  return "?";
}

static void
bgp_show_capabilities(struct bgp_proto *p UNUSED, struct bgp_caps *caps)
{
  struct bgp_af_caps *ac;
  uint any_mp_bgp = 0;
  uint any_gr_able = 0;
  uint any_add_path = 0;
  uint any_ext_next_hop = 0;
  uint any_llgr_able = 0;
  u32 *afl1 = alloca(caps->af_count * sizeof(u32));
  u32 *afl2 = alloca(caps->af_count * sizeof(u32));
  uint afn1, afn2;

  WALK_AF_CAPS(caps, ac)
  {
    any_mp_bgp |= ac->ready;
    any_gr_able |= ac->gr_able;
    any_add_path |= ac->add_path;
    any_ext_next_hop |= ac->ext_next_hop;
    any_llgr_able |= ac->llgr_able;
  }

  if (any_mp_bgp)
  {
    cli_msg(-1006, "      Multiprotocol");

    afn1 = 0;
    WALK_AF_CAPS(caps, ac)
      if (ac->ready)
	afl1[afn1++] = ac->afi;

    bgp_show_afis(-1006, "        AF announced:", afl1, afn1);
  }

  if (caps->route_refresh)
    cli_msg(-1006, "      Route refresh");

  if (any_ext_next_hop)
  {
    cli_msg(-1006, "      Extended next hop");

    afn1 = 0;
    WALK_AF_CAPS(caps, ac)
      if (ac->ext_next_hop)
	afl1[afn1++] = ac->afi;

    bgp_show_afis(-1006, "        IPv6 nexthop:", afl1, afn1);
  }

  if (caps->ext_messages)
    cli_msg(-1006, "      Extended message");

  if (caps->gr_aware)
    cli_msg(-1006, "      Graceful restart");

  if (any_gr_able)
  {
    /* Continues from gr_aware */
    cli_msg(-1006, "        Restart time: %u", caps->gr_time);
    if (caps->gr_flags & BGP_GRF_RESTART)
      cli_msg(-1006, "        Restart recovery");

    afn1 = afn2 = 0;
    WALK_AF_CAPS(caps, ac)
    {
      if (ac->gr_able)
	afl1[afn1++] = ac->afi;

      if (ac->gr_af_flags & BGP_GRF_FORWARDING)
	afl2[afn2++] = ac->afi;
    }

    bgp_show_afis(-1006, "        AF supported:", afl1, afn1);
    bgp_show_afis(-1006, "        AF preserved:", afl2, afn2);
  }

  if (caps->as4_support)
    cli_msg(-1006, "      4-octet AS numbers");

  if (any_add_path)
  {
    cli_msg(-1006, "      ADD-PATH");

    afn1 = afn2 = 0;
    WALK_AF_CAPS(caps, ac)
    {
      if (ac->add_path & BGP_ADD_PATH_RX)
	afl1[afn1++] = ac->afi;

      if (ac->add_path & BGP_ADD_PATH_TX)
	afl2[afn2++] = ac->afi;
    }

    bgp_show_afis(-1006, "        RX:", afl1, afn1);
    bgp_show_afis(-1006, "        TX:", afl2, afn2);
  }

  if (caps->enhanced_refresh)
    cli_msg(-1006, "      Enhanced refresh");

  if (caps->llgr_aware)
    cli_msg(-1006, "      Long-lived graceful restart");

  if (any_llgr_able)
  {
    u32 stale_time = 0;

    afn1 = afn2 = 0;
    WALK_AF_CAPS(caps, ac)
    {
      stale_time = MAX(stale_time, ac->llgr_time);

      if (ac->llgr_able && ac->llgr_time)
	afl1[afn1++] = ac->afi;

      if (ac->llgr_flags & BGP_GRF_FORWARDING)
	afl2[afn2++] = ac->afi;
    }

    /* Continues from llgr_aware */
    cli_msg(-1006, "        LL stale time: %u", stale_time);

    bgp_show_afis(-1006, "        AF supported:", afl1, afn1);
    bgp_show_afis(-1006, "        AF preserved:", afl2, afn2);
  }

  if (caps->hostname)
    cli_msg(-1006, "      Hostname: %s", caps->hostname);

  if (caps->role != BGP_ROLE_UNDEFINED)
    cli_msg(-1006, "      Role: %s", bgp_format_role_name(caps->role));
}

static void
bgp_show_proto_info(struct proto *P)
{
  struct bgp_proto *p = (struct bgp_proto *) P;

  cli_msg(-1006, "  BGP state:          %s", bgp_state_dsc(p));

  if (bgp_is_dynamic(p) && p->cf->remote_range)
    cli_msg(-1006, "    Neighbor range:   %N", p->cf->remote_range);
  else
    cli_msg(-1006, "    Neighbor address: %I%J", p->remote_ip, p->cf->iface);

  if ((p->conn == &p->outgoing_conn) && (p->cf->remote_port != BGP_PORT))
    cli_msg(-1006, "    Neighbor port:    %u", p->cf->remote_port);

  cli_msg(-1006, "    Neighbor AS:      %u", p->remote_as);
  cli_msg(-1006, "    Local AS:         %u", p->cf->local_as);

  if (p->gr_active_num)
    cli_msg(-1006, "    Neighbor graceful restart active");

  if (P->proto_state == PS_START)
  {
    struct bgp_conn *oc = &p->outgoing_conn;

    if ((p->start_state < BSS_CONNECT) &&
	(tm_active(p->startup_timer)))
      cli_msg(-1006, "    Error wait:       %t/%u",
	      tm_remains(p->startup_timer), p->startup_delay);

    if ((oc->state == BS_ACTIVE) &&
	(tm_active(oc->connect_timer)))
      cli_msg(-1006, "    Connect delay:    %t/%u",
	      tm_remains(oc->connect_timer), p->cf->connect_delay_time);

    if (p->gr_active_num && tm_active(p->gr_timer))
      cli_msg(-1006, "    Restart timer:    %t/-",
	      tm_remains(p->gr_timer));
  }
  else if (P->proto_state == PS_UP)
  {
    cli_msg(-1006, "    Neighbor ID:      %R", p->remote_id);
    cli_msg(-1006, "    Local capabilities");
    bgp_show_capabilities(p, p->conn->local_caps);
    cli_msg(-1006, "    Neighbor capabilities");
    bgp_show_capabilities(p, p->conn->remote_caps);
    cli_msg(-1006, "    Session:          %s%s%s%s%s",
	    p->is_internal ? "internal" : "external",
	    p->cf->multihop ? " multihop" : "",
	    p->rr_client ? " route-reflector" : "",
	    p->rs_client ? " route-server" : "",
	    p->as4_session ? " AS4" : "");
    cli_msg(-1006, "    Source address:   %I", p->local_ip);
    cli_msg(-1006, "    Hold timer:       %t/%u",
	    tm_remains(p->conn->hold_timer), p->conn->hold_time);
    cli_msg(-1006, "    Keepalive timer:  %t/%u",
	    tm_remains(p->conn->keepalive_timer), p->conn->keepalive_time);
  }

#if 0
  struct bgp_stats *s = &p->stats;
  cli_msg(-1006, "    FSM established transitions: %u",
	  s->fsm_established_transitions);
  cli_msg(-1006, "    Rcvd messages:    %u total / %u updates / %lu bytes",
	  s->rx_messages, s->rx_updates, s->rx_bytes);
  cli_msg(-1006, "    Sent messages:    %u total / %u updates / %lu bytes",
	  s->tx_messages, s->tx_updates, s->tx_bytes);
  cli_msg(-1006, "    Last rcvd update elapsed time: %t s",
	  p->last_rx_update ? (current_time() - p->last_rx_update) : 0);
#endif

  if ((p->last_error_class != BE_NONE) &&
      (p->last_error_class != BE_MAN_DOWN))
  {
    const char *err1 = bgp_err_classes[p->last_error_class];
    const char *err2 = bgp_last_errmsg(p);
    cli_msg(-1006, "    Last error:       %s%s", err1, err2);
  }

  {
    struct bgp_channel *c;
    WALK_LIST(c, p->p.channels)
    {
      channel_show_info(&c->c);

      if (p->gr_active_num)
	cli_msg(-1006, "    Neighbor GR:    %s", bgp_gr_states[c->gr_active]);

      if (c->stale_timer && tm_active(c->stale_timer))
	cli_msg(-1006, "    LL stale timer: %t/-", tm_remains(c->stale_timer));

      if (c->c.channel_state == CS_UP)
      {
	if (ipa_zero(c->link_addr))
	  cli_msg(-1006, "    BGP Next hop:   %I", c->next_hop_addr);
	else
	  cli_msg(-1006, "    BGP Next hop:   %I %I", c->next_hop_addr, c->link_addr);
      }

      if (c->igp_table_ip4)
	cli_msg(-1006, "    IGP IPv4 table: %s", c->igp_table_ip4->name);

      if (c->igp_table_ip6)
	cli_msg(-1006, "    IGP IPv6 table: %s", c->igp_table_ip6->name);

      if (c->base_table)
	cli_msg(-1006, "    Base table:     %s", c->base_table->name);
    }
  }
}

struct channel_class channel_bgp = {
  .channel_size =	sizeof(struct bgp_channel),
  .config_size =	sizeof(struct bgp_channel_config),
  .init =		bgp_channel_init,
  .start =		bgp_channel_start,
  .shutdown =		bgp_channel_shutdown,
  .cleanup =		bgp_channel_cleanup,
  .reconfigure =	bgp_channel_reconfigure,
};

struct protocol proto_bgp = {
  .name = 		"BGP",
  .template = 		"bgp%d",
  .preference = 	DEF_PREF_BGP,
  .channel_mask =	NB_IP | NB_VPN | NB_FLOW,
  .proto_size =		sizeof(struct bgp_proto),
  .config_size =	sizeof(struct bgp_config),
  .postconfig =		bgp_postconfig,
  .init = 		bgp_init,
  .start = 		bgp_start,
  .shutdown = 		bgp_shutdown,
  .reconfigure = 	bgp_reconfigure,
  .copy_config = 	bgp_copy_config,
  .get_status = 	bgp_get_status,
  .show_proto_info = 	bgp_show_proto_info
};

void bgp_build(void)
{
  proto_build(&proto_bgp);
  bgp_register_attrs();
}