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