proto/bgp/bgp.h

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