1: /*
2: * BIRD -- The Border Gateway Protocol
3: *
4: * (c) 2000 Martin Mares <mj@ucw.cz>
5: *
6: * Can be freely distributed and used under the terms of the GNU GPL.
7: */
8:
9: #ifndef _BIRD_BGP_H_
10: #define _BIRD_BGP_H_
11:
12: #include <stdint.h>
13: #include "nest/route.h"
14: #include "nest/bfd.h"
15: #include "lib/hash.h"
16:
17: struct linpool;
18: struct eattr;
19:
20: struct bgp_config {
21: struct proto_config c;
22: u32 local_as, remote_as;
23: ip_addr remote_ip;
24: ip_addr source_addr; /* Source address to use */
25: struct iface *iface; /* Interface for link-local addresses */
26: u16 remote_port; /* Neighbor destination port */
27: int multihop; /* Number of hops if multihop */
28: int ttl_security; /* Enable TTL security [RFC5082] */
29: int next_hop_self; /* Always set next hop to local IP address */
30: int next_hop_keep; /* Do not touch next hop attribute */
31: int missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
32: int gw_mode; /* How we compute route gateway from next_hop attr, see GW_* */
33: int compare_path_lengths; /* Use path lengths when selecting best route */
34: int med_metric; /* Compare MULTI_EXIT_DISC even between routes from differen ASes */
35: int igp_metric; /* Use IGP metrics when selecting best route */
36: int prefer_older; /* Prefer older routes according to RFC 5004 */
37: int deterministic_med; /* Use more complicated algo to have strict RFC 4271 MED comparison */
38: u32 default_local_pref; /* Default value for LOCAL_PREF attribute */
39: u32 default_med; /* Default value for MULTI_EXIT_DISC attribute */
40: int capabilities; /* Enable capability handshake [RFC3392] */
41: int enable_refresh; /* Enable local support for route refresh [RFC2918] */
42: int enable_as4; /* Enable local support for 4B AS numbers [RFC4893] */
43: int enable_extended_messages; /* Enable local support for extended messages [draft] */
44: u32 rr_cluster_id; /* Route reflector cluster ID, if different from local ID */
45: int rr_client; /* Whether neighbor is RR client of me */
46: int rs_client; /* Whether neighbor is RS client of me */
47: int advertise_ipv4; /* Whether we should add IPv4 capability advertisement to OPEN message */
48: int passive; /* Do not initiate outgoing connection */
49: int interpret_communities; /* Hardwired handling of well-known communities */
50: int secondary; /* Accept also non-best routes (i.e. RA_ACCEPTED) */
51: int add_path; /* Use ADD-PATH extension [RFC7911] */
52: int allow_local_as; /* Allow that number of local ASNs in incoming AS_PATHs */
53: int allow_local_pref; /* Allow LOCAL_PREF in EBGP sessions */
54: int gr_mode; /* Graceful restart mode (BGP_GR_*) */
55: int llgr_mode; /* Long-lived graceful restart mode (BGP_LLGR_*) */
56: int setkey; /* Set MD5 password to system SA/SP database */
57: unsigned gr_time; /* Graceful restart timeout */
58: unsigned llgr_time; /* Long-lived graceful restart timeout */
59: unsigned connect_delay_time; /* Minimum delay between connect attempts */
60: unsigned connect_retry_time; /* Timeout for connect attempts */
61: unsigned hold_time, initial_hold_time;
62: unsigned keepalive_time;
63: unsigned error_amnesia_time; /* Errors are forgotten after */
64: unsigned error_delay_time_min; /* Time to wait after an error is detected */
65: unsigned error_delay_time_max;
66: unsigned disable_after_error; /* Disable the protocol when error is detected */
67: u32 disable_after_cease; /* Disable it when cease is received, bitfield */
68:
69: char *password; /* Password used for MD5 authentication */
70: struct rtable_config *igp_table; /* Table used for recursive next hop lookups */
71: int check_link; /* Use iface link state for liveness detection */
72: int bfd; /* Use BFD for liveness detection */
73: };
74:
75: #define MLL_SELF 1
76: #define MLL_DROP 2
77: #define MLL_IGNORE 3
78:
79: #define GW_DIRECT 1
80: #define GW_RECURSIVE 2
81:
82: #define ADD_PATH_RX 1
83: #define ADD_PATH_TX 2
84: #define ADD_PATH_FULL 3
85:
86: #define BGP_GR_ABLE 1
87: #define BGP_GR_AWARE 2
88:
89: /* For peer_gr_flags */
90: #define BGP_GRF_RESTART 0x80
91:
92: /* For peer_gr_aflags */
93: #define BGP_GRF_FORWARDING 0x80
94:
95: #define BGP_LLGR_ABLE 1
96: #define BGP_LLGR_AWARE 2
97:
98: #define BGP_LLGRF_FORWARDING 0x80
99:
100: #define BGP_GRS_NONE 0 /* No GR */
101: #define BGP_GRS_ACTIVE 1 /* Graceful restart per RFC 4724 */
102: #define BGP_GRS_LLGR_1 2 /* Long-lived GR phase 1 (restart time) */
103: #define BGP_GRS_LLGR_2 3 /* Long-lived GR phase 2 (stale time) */
104:
105: #define BGP_BFD_GRACEFUL 2 /* BFD down triggers graceful restart */
106:
107:
108: struct bgp_conn {
109: struct bgp_proto *bgp;
110: struct birdsock *sk;
111: uint state; /* State of connection state machine */
112: struct timer *connect_retry_timer;
113: struct timer *hold_timer;
114: struct timer *keepalive_timer;
115: struct event *tx_ev;
116: int packets_to_send; /* Bitmap of packet types to be sent */
117: int notify_code, notify_subcode, notify_size;
118: byte *notify_data;
119: u32 advertised_as; /* Temporary value for AS number received */
120: int start_state; /* protocol start_state snapshot when connection established */
121: u8 peer_refresh_support; /* Peer supports route refresh [RFC2918] */
122: u8 peer_as4_support; /* Peer supports 4B AS numbers [RFC4893] */
123: u8 peer_add_path; /* Peer supports ADD-PATH [RFC7911] */
124: u8 peer_enhanced_refresh_support; /* Peer supports enhanced refresh [RFC7313] */
125: u8 peer_gr_aware;
126: u8 peer_gr_able;
127: u16 peer_gr_time;
128: u8 peer_gr_flags;
129: u8 peer_gr_aflags;
130: u8 peer_llgr_aware;
131: u8 peer_llgr_able;
132: uint peer_llgr_time;
133: u8 peer_llgr_aflags;
134: u8 peer_ext_messages_support; /* Peer supports extended message length [draft] */
135: unsigned hold_time, keepalive_time; /* Times calculated from my and neighbor's requirements */
136: };
137:
138: struct bgp_proto {
139: struct proto p;
140: struct bgp_config *cf; /* Shortcut to BGP configuration */
141: u32 local_as, remote_as;
142: int start_state; /* Substates that partitions BS_START */
143: u8 is_internal; /* Internal BGP connection (local_as == remote_as) */
144: u8 as4_session; /* Session uses 4B AS numbers in AS_PATH (both sides support it) */
145: u8 add_path_rx; /* Session expects receive of ADD-PATH extended NLRI */
146: u8 add_path_tx; /* Session expects transmit of ADD-PATH extended NLRI */
147: u8 ext_messages; /* Session allows to use extended messages (both sides support it) */
148: u32 local_id; /* BGP identifier of this router */
149: u32 remote_id; /* BGP identifier of the neighbor */
150: u32 rr_cluster_id; /* Route reflector cluster ID */
151: int rr_client; /* Whether neighbor is RR client of me */
152: int rs_client; /* Whether neighbor is RS client of me */
153: u8 gr_ready; /* Neighbor could do graceful restart */
154: u8 gr_active; /* Neighbor is doing graceful restart (BGP_GRS_*) */
155: u8 feed_state; /* Feed state (TX) for EoR, RR packets, see BFS_* */
156: u8 load_state; /* Load state (RX) for EoR, RR packets, see BFS_* */
157: uint stale_time; /* Long-lived stale time for LLGR */
158: struct bgp_conn *conn; /* Connection we have established */
159: struct bgp_conn outgoing_conn; /* Outgoing connection we're working with */
160: struct bgp_conn incoming_conn; /* Incoming connection we have neither accepted nor rejected yet */
161: struct object_lock *lock; /* Lock for neighbor connection */
162: struct neighbor *neigh; /* Neighbor entry corresponding to remote ip, NULL if multihop */
163: struct bfd_request *bfd_req; /* BFD request, if BFD is used */
164: ip_addr source_addr; /* Local address used as an advertised next hop */
165: rtable *igp_table; /* Table used for recursive next hop lookups */
166: struct event *event; /* Event for respawning and shutting process */
167: struct timer *startup_timer; /* Timer used to delay protocol startup due to previous errors (startup_delay) */
168: struct timer *gr_timer; /* Timer waiting for reestablishment after graceful restart */
169: struct bgp_bucket **bucket_hash; /* Hash table of attribute buckets */
170: uint hash_size, hash_count, hash_limit;
171: HASH(struct bgp_prefix) prefix_hash; /* Prefixes to be sent */
172: slab *prefix_slab; /* Slab holding prefix nodes */
173: list bucket_queue; /* Queue of buckets to send */
174: struct bgp_bucket *withdraw_bucket; /* Withdrawn routes */
175: unsigned startup_delay; /* Time to delay protocol startup by due to errors */
176: bird_clock_t last_proto_error; /* Time of last error that leads to protocol stop */
177: u8 last_error_class; /* Error class of last error */
178: u32 last_error_code; /* Error code of last error. BGP protocol errors
179: are encoded as (bgp_err_code << 16 | bgp_err_subcode) */
180: #ifdef IPV6
181: byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute notes */
182: unsigned mp_reach_len, mp_unreach_len;
183: ip_addr local_link; /* Link-level version of source_addr */
184: #endif
185: };
186:
187: struct bgp_prefix {
188: struct {
189: ip_addr prefix;
190: int pxlen;
191: } n;
192: u32 path_id;
193: struct bgp_prefix *next;
194: node bucket_node; /* Node in per-bucket list */
195: };
196:
197: struct bgp_bucket {
198: node send_node; /* Node in send queue */
199: struct bgp_bucket *hash_next, *hash_prev; /* Node in bucket hash table */
200: unsigned hash; /* Hash over extended attributes */
201: list prefixes; /* Prefixes in this buckets */
202: ea_list eattrs[0]; /* Per-bucket extended attributes */
203: };
204:
205: #define BGP_PORT 179
206: #define BGP_VERSION 4
207: #define BGP_HEADER_LENGTH 19
208: #define BGP_MAX_MESSAGE_LENGTH 4096
209: #define BGP_MAX_EXT_MSG_LENGTH 65535
210: #define BGP_RX_BUFFER_SIZE 4096
211: #define BGP_TX_BUFFER_SIZE 4096
212: #define BGP_RX_BUFFER_EXT_SIZE 65535
213: #define BGP_TX_BUFFER_EXT_SIZE 65535
214:
215: static inline uint bgp_max_packet_length(struct bgp_proto *p)
216: { return p->ext_messages ? BGP_MAX_EXT_MSG_LENGTH : BGP_MAX_MESSAGE_LENGTH; }
217:
218: extern struct linpool *bgp_linpool;
219:
220:
221: void bgp_start_timer(struct timer *t, int value);
222: void bgp_check_config(struct bgp_config *c);
223: void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len);
224: void bgp_close_conn(struct bgp_conn *c);
225: void bgp_update_startup_delay(struct bgp_proto *p);
226: void bgp_conn_enter_openconfirm_state(struct bgp_conn *conn);
227: void bgp_conn_enter_established_state(struct bgp_conn *conn);
228: void bgp_conn_enter_close_state(struct bgp_conn *conn);
229: void bgp_conn_enter_idle_state(struct bgp_conn *conn);
230: void bgp_handle_graceful_restart(struct bgp_proto *p);
231: void bgp_graceful_restart_done(struct bgp_proto *p);
232: void bgp_refresh_begin(struct bgp_proto *p);
233: void bgp_refresh_end(struct bgp_proto *p);
234: void bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code);
235: void bgp_stop(struct bgp_proto *p, uint subcode, byte *data, uint len);
236:
237: struct rte_source *bgp_find_source(struct bgp_proto *p, u32 path_id);
238: struct rte_source *bgp_get_source(struct bgp_proto *p, u32 path_id);
239:
240:
241:
242: #ifdef LOCAL_DEBUG
243: #define BGP_FORCE_DEBUG 1
244: #else
245: #define BGP_FORCE_DEBUG 0
246: #endif
247: #define BGP_TRACE(flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
248: log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
249:
250: #define BGP_TRACE_RL(rl, flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
251: log_rl(rl, L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
252:
253:
254: /* attrs.c */
255:
256: /* Hack: although BA_NEXT_HOP attribute has type EAF_TYPE_IP_ADDRESS, in IPv6
257: * we store two addesses in it - a global address and a link local address.
258: */
259: #ifdef IPV6
260: #define NEXT_HOP_LENGTH (2*sizeof(ip_addr))
261: static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; ((ip_addr *) b)[1] = IPA_NONE; }
262: #else
263: #define NEXT_HOP_LENGTH sizeof(ip_addr)
264: static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; }
265: #endif
266:
267: void bgp_attach_attr(struct ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val);
268: byte *bgp_attach_attr_wa(struct ea_list **to, struct linpool *pool, unsigned attr, unsigned len);
269: struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, uint len, struct linpool *pool, int mandatory);
270: int bgp_get_attr(struct eattr *e, byte *buf, int buflen);
271: int bgp_rte_better(struct rte *, struct rte *);
272: int bgp_rte_mergable(rte *pri, rte *sec);
273: int bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best);
274: struct rte *bgp_rte_modify_stale(struct rte *r, struct linpool *pool);
275: void bgp_rt_notify(struct proto *P, rtable *tbl UNUSED, net *n, rte *new, rte *old UNUSED, ea_list *attrs);
276: int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
277: void bgp_init_bucket_table(struct bgp_proto *);
278: void bgp_free_bucket_table(struct bgp_proto *p);
279: void bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck);
280: void bgp_init_prefix_table(struct bgp_proto *p, u32 order);
281: void bgp_free_prefix_table(struct bgp_proto *p);
282: void bgp_free_prefix(struct bgp_proto *p, struct bgp_prefix *bp);
283: uint bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains);
284: void bgp_get_route_info(struct rte *, byte *buf, struct ea_list *attrs);
285:
286: inline static void bgp_attach_attr_ip(struct ea_list **to, struct linpool *pool, unsigned attr, ip_addr a)
287: { *(ip_addr *) bgp_attach_attr_wa(to, pool, attr, sizeof(ip_addr)) = a; }
288:
289: /* packets.c */
290:
291: void bgp_dump_state_change(struct bgp_conn *conn, uint old, uint new);
292: void bgp_schedule_packet(struct bgp_conn *conn, int type);
293: void bgp_kick_tx(void *vconn);
294: void bgp_tx(struct birdsock *sk);
295: int bgp_rx(struct birdsock *sk, uint size);
296: const char * bgp_error_dsc(unsigned code, unsigned subcode);
297: void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len);
298:
299: /* Packet types */
300:
301: #define PKT_OPEN 0x01
302: #define PKT_UPDATE 0x02
303: #define PKT_NOTIFICATION 0x03
304: #define PKT_KEEPALIVE 0x04
305: #define PKT_ROUTE_REFRESH 0x05 /* [RFC2918] */
306: #define PKT_BEGIN_REFRESH 0x1e /* Dummy type for BoRR packet [RFC7313] */
307: #define PKT_SCHEDULE_CLOSE 0x1f /* Used internally to schedule socket close */
308:
309: /* Attributes */
310:
311: #define BAF_OPTIONAL 0x80
312: #define BAF_TRANSITIVE 0x40
313: #define BAF_PARTIAL 0x20
314: #define BAF_EXT_LEN 0x10
315:
316: #define BA_ORIGIN 0x01 /* [RFC1771] */ /* WM */
317: #define BA_AS_PATH 0x02 /* WM */
318: #define BA_NEXT_HOP 0x03 /* WM */
319: #define BA_MULTI_EXIT_DISC 0x04 /* ON */
320: #define BA_LOCAL_PREF 0x05 /* WD */
321: #define BA_ATOMIC_AGGR 0x06 /* WD */
322: #define BA_AGGREGATOR 0x07 /* OT */
323: #define BA_COMMUNITY 0x08 /* [RFC1997] */ /* OT */
324: #define BA_ORIGINATOR_ID 0x09 /* [RFC1966] */ /* ON */
325: #define BA_CLUSTER_LIST 0x0a /* ON */
326: /* We don't support these: */
327: #define BA_DPA 0x0b /* ??? */
328: #define BA_ADVERTISER 0x0c /* [RFC1863] */
329: #define BA_RCID_PATH 0x0d
330: #define BA_MP_REACH_NLRI 0x0e /* [RFC2283] */
331: #define BA_MP_UNREACH_NLRI 0x0f
332: #define BA_EXT_COMMUNITY 0x10 /* [RFC4360] */
333: #define BA_AS4_PATH 0x11 /* [RFC4893] */
334: #define BA_AS4_AGGREGATOR 0x12
335: #define BA_LARGE_COMMUNITY 0x20 /* [RFC8092] */
336:
337: /* BGP connection states */
338:
339: #define BS_IDLE 0
340: #define BS_CONNECT 1 /* Attempting to connect */
341: #define BS_ACTIVE 2 /* Waiting for connection retry & listening */
342: #define BS_OPENSENT 3
343: #define BS_OPENCONFIRM 4
344: #define BS_ESTABLISHED 5
345: #define BS_CLOSE 6 /* Used during transition to BS_IDLE */
346:
347: #define BS_MAX 7
348:
349: /* BGP start states
350: *
351: * Used in PS_START for fine-grained specification of starting state.
352: *
353: * When BGP protocol is started by core, it goes to BSS_PREPARE. When BGP
354: * protocol done what is neccessary to start itself (like acquiring the lock),
355: * it goes to BSS_CONNECT. When some connection attempt failed because of
356: * option or capability error, it goes to BSS_CONNECT_NOCAP.
357: */
358:
359: #define BSS_PREPARE 0 /* Used before ordinary BGP started, i. e. waiting for lock */
360: #define BSS_DELAY 1 /* Startup delay due to previous errors */
361: #define BSS_CONNECT 2 /* Ordinary BGP connecting */
362: #define BSS_CONNECT_NOCAP 3 /* Legacy BGP connecting (without capabilities) */
363:
364:
365: /* BGP feed states (TX)
366: *
367: * RFC 4724 specifies that an initial feed should end with End-of-RIB mark.
368: *
369: * RFC 7313 specifies that a route refresh should be demarcated by BoRR and EoRR packets.
370: *
371: * These states (stored in p->feed_state) are used to keep track of these
372: * requirements. When such feed is started, BFS_LOADING / BFS_REFRESHING is
373: * set. When it ended, BFS_LOADED / BFS_REFRESHED is set to schedule End-of-RIB
374: * or EoRR packet. When the packet is sent, the state returned to BFS_NONE.
375: *
376: * Note that when a non-demarcated feed (e.g. plain RFC 4271 initial load
377: * without End-of-RIB or plain RFC 2918 route refresh without BoRR/EoRR
378: * demarcation) is active, BFS_NONE is set.
379: *
380: * BFS_NONE, BFS_LOADING and BFS_REFRESHING are also used as load states (RX)
381: * with correspondent semantics (-, expecting End-of-RIB, expecting EoRR).
382: */
383:
384: #define BFS_NONE 0 /* No feed or original non-demarcated feed */
385: #define BFS_LOADING 1 /* Initial feed active, End-of-RIB planned */
386: #define BFS_LOADED 2 /* Loading done, End-of-RIB marker scheduled */
387: #define BFS_REFRESHING 3 /* Route refresh (introduced by BoRR) active */
388: #define BFS_REFRESHED 4 /* Refresh done, EoRR packet scheduled */
389:
390:
391: /* Error classes */
392:
393: #define BE_NONE 0
394: #define BE_MISC 1 /* Miscellaneous error */
395: #define BE_SOCKET 2 /* Socket error */
396: #define BE_BGP_RX 3 /* BGP protocol error notification received */
397: #define BE_BGP_TX 4 /* BGP protocol error notification sent */
398: #define BE_AUTO_DOWN 5 /* Automatic shutdown */
399: #define BE_MAN_DOWN 6 /* Manual shutdown */
400:
401: /* Misc error codes */
402:
403: #define BEM_NEIGHBOR_LOST 1
404: #define BEM_INVALID_NEXT_HOP 2
405: #define BEM_INVALID_MD5 3 /* MD5 authentication kernel request failed (possibly not supported) */
406: #define BEM_NO_SOCKET 4
407: #define BEM_LINK_DOWN 5
408: #define BEM_BFD_DOWN 6
409: #define BEM_GRACEFUL_RESTART 7
410:
411: /* Automatic shutdown error codes */
412:
413: #define BEA_ROUTE_LIMIT_EXCEEDED 1
414:
415: /* Well-known communities */
416:
417: #define BGP_COMM_NO_EXPORT 0xffffff01 /* Don't export outside local AS / confed. */
418: #define BGP_COMM_NO_ADVERTISE 0xffffff02 /* Don't export at all */
419: #define BGP_COMM_NO_EXPORT_SUBCONFED 0xffffff03 /* NO_EXPORT even in local confederation */
420:
421: #define BGP_COMM_LLGR_STALE 0xffff0006 /* Route is stale according to LLGR */
422: #define BGP_COMM_NO_LLGR 0xffff0007 /* Do not treat the route according to LLGR */
423:
424: /* Origins */
425:
426: #define ORIGIN_IGP 0
427: #define ORIGIN_EGP 1
428: #define ORIGIN_INCOMPLETE 2
429:
430: /* Address families */
431:
432: #define BGP_AF_IPV4 1
433: #define BGP_AF_IPV6 2
434:
435: #ifdef IPV6
436: #define BGP_AF BGP_AF_IPV6
437: #else
438: #define BGP_AF BGP_AF_IPV4
439: #endif
440:
441: #endif
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