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
  16 struct linpool;
  17 struct eattr;
  18
  19 struct bgp_config {
  20   struct proto_config c;
  21   u32 local_as, remote_as;
  22   ip_addr remote_ip;
  23   ip_addr source_addr;                  /* Source address to use */
  24   struct iface *iface;                  /* Interface for link-local addresses */
  25   int multihop;                         /* Number of hops if multihop */
  26   int ttl_security;                     /* Enable TTL security [RFC5082] */
  27   int next_hop_self;                    /* Always set next hop to local IP address */
  28   int next_hop_keep;                    /* Do not touch next hop attribute */
  29   int missing_lladdr;                   /* What we will do when we don' know link-local addr, see MLL_* */
  30   int gw_mode;                          /* How we compute route gateway from next_hop attr, see GW_* */
  31   int compare_path_lengths;             /* Use path lengths when selecting best route */
  32   int med_metric;                       /* Compare MULTI_EXIT_DISC even between routes from differen ASes */
  33   int igp_metric;                       /* Use IGP metrics when selecting best route */
  34   int prefer_older;                     /* Prefer older routes according to RFC 5004 */
  35   int deterministic_med;                /* Use more complicated algo to have strict RFC 4271 MED comparison */
  36   u32 default_local_pref;               /* Default value for LOCAL_PREF attribute */
  37   u32 default_med;                      /* Default value for MULTI_EXIT_DISC attribute */
  38   int capabilities;                     /* Enable capability handshake [RFC3392] */
  39   int enable_refresh;                   /* Enable local support for route refresh [RFC2918] */
  40   int enable_as4;                       /* Enable local support for 4B AS numbers [RFC4893] */
  41   u32 rr_cluster_id;                    /* Route reflector cluster ID, if different from local ID */
  42   int rr_client;                        /* Whether neighbor is RR client of me */
  43   int rs_client;                        /* Whether neighbor is RS client of me */
  44   int advertise_ipv4;                   /* Whether we should add IPv4 capability advertisement to OPEN message */
  45   int passive;                          /* Do not initiate outgoing connection */
  46   int interpret_communities;            /* Hardwired handling of well-known communities */
  47   int secondary;                        /* Accept also non-best routes (i.e. RA_ACCEPTED) */
  48   int add_path;                         /* Use ADD-PATH extension [draft] */
  49   int allow_local_as;                   /* Allow that number of local ASNs in incoming AS_PATHs */
  50   unsigned connect_retry_time;
  51   unsigned hold_time, initial_hold_time;
  52   unsigned keepalive_time;
  53   unsigned start_delay_time;            /* Minimum delay between connects */
  54   unsigned error_amnesia_time;          /* Errors are forgotten after */
  55   unsigned error_delay_time_min;        /* Time to wait after an error is detected */
  56   unsigned error_delay_time_max;
  57   unsigned disable_after_error;         /* Disable the protocol when error is detected */
  58
  59   char *password;                       /* Password used for MD5 authentication */
  60   struct rtable_config *igp_table;      /* Table used for recursive next hop lookups */
  61   int bfd;                              /* Use BFD for liveness detection */
  62 };
  63
  64 #define MLL_SELF 1
  65 #define MLL_DROP 2
  66 #define MLL_IGNORE 3
  67
  68 #define GW_DIRECT 1
  69 #define GW_RECURSIVE 2
  70
  71 #define ADD_PATH_RX 1
  72 #define ADD_PATH_TX 2
  73 #define ADD_PATH_FULL 3
  74
  75
  76 struct bgp_conn {
  77   struct bgp_proto *bgp;
  78   struct birdsock *sk;
  79   unsigned int state;                   /* State of connection state machine */
  80   struct timer *connect_retry_timer;
  81   struct timer *hold_timer;
  82   struct timer *keepalive_timer;
  83   struct event *tx_ev;
  84   int packets_to_send;                  /* Bitmap of packet types to be sent */
  85   int notify_code, notify_subcode, notify_size;
  86   byte *notify_data;
  87   u32 advertised_as;                    /* Temporary value for AS number received */
  88   int start_state;                      /* protocol start_state snapshot when connection established */
  89   u8 peer_refresh_support;              /* Peer supports route refresh [RFC2918] */
  90   u8 peer_as4_support;                  /* Peer supports 4B AS numbers [RFC4893] */
  91   u8 peer_add_path;                     /* Peer supports ADD-PATH [draft] */
  92   unsigned hold_time, keepalive_time;   /* Times calculated from my and neighbor's requirements */
  93 };
  94
  95 struct bgp_proto {
  96   struct proto p;
  97   struct bgp_config *cf;                /* Shortcut to BGP configuration */
  98   u32 local_as, remote_as;
  99   int start_state;                      /* Substates that partitions BS_START */
 100   u8 is_internal;                       /* Internal BGP connection (local_as == remote_as) */
 101   u8 as4_session;                       /* Session uses 4B AS numbers in AS_PATH (both sides support it) */
 102   u8 add_path_rx;                       /* Session expects receive of ADD-PATH extended NLRI */
 103   u8 add_path_tx;                       /* Session expects transmit of ADD-PATH extended NLRI */
 104   u32 local_id;                         /* BGP identifier of this router */
 105   u32 remote_id;                        /* BGP identifier of the neighbor */
 106   u32 rr_cluster_id;                    /* Route reflector cluster ID */
 107   int rr_client;                        /* Whether neighbor is RR client of me */
 108   int rs_client;                        /* Whether neighbor is RS client of me */
 109   struct bgp_conn *conn;                /* Connection we have established */
 110   struct bgp_conn outgoing_conn;        /* Outgoing connection we're working with */
 111   struct bgp_conn incoming_conn;        /* Incoming connection we have neither accepted nor rejected yet */
 112   struct object_lock *lock;             /* Lock for neighbor connection */
 113   struct neighbor *neigh;               /* Neighbor entry corresponding to remote ip, NULL if multihop */
 114   struct bfd_request *bfd_req;          /* BFD request, if BFD is used */
 115   ip_addr source_addr;                  /* Local address used as an advertised next hop */
 116   rtable *igp_table;                    /* Table used for recursive next hop lookups */
 117   struct event *event;                  /* Event for respawning and shutting process */
 118   struct timer *startup_timer;          /* Timer used to delay protocol startup due to previous errors (startup_delay) */
 119   struct bgp_bucket **bucket_hash;      /* Hash table of attribute buckets */
 120   unsigned int hash_size, hash_count, hash_limit;
 121   // struct fib prefix_fib;             /* Prefixes to be sent */
 122   struct bgp_prefix **prefix_table;     /* Prefixes to be sent */
 123   slab *prefix_slab;                    /* Slab holding prefix nodes */
 124   u32 px_hash_order, px_hash_count;
 125   list bucket_queue;                    /* Queue of buckets to send */
 126   struct bgp_bucket *withdraw_bucket;   /* Withdrawn routes */
 127   unsigned startup_delay;               /* Time to delay protocol startup by due to errors */
 128   bird_clock_t last_proto_error;        /* Time of last error that leads to protocol stop */
 129   u8 last_error_class;                  /* Error class of last error */
 130   u32 last_error_code;                  /* Error code of last error. BGP protocol errors
 131                                            are encoded as (bgp_err_code << 16 | bgp_err_subcode) */
 132 #ifdef IPV6
 133   byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute notes */
 134   unsigned mp_reach_len, mp_unreach_len;
 135   ip_addr local_link;                   /* Link-level version of source_addr */
 136 #endif
 137 };
 138
 139 struct bgp_prefix {
 140   struct {
 141     ip_addr prefix;
 142     int pxlen;
 143   } n;
 144   u32 path_id;
 145   struct bgp_prefix *next;
 146   node bucket_node;                     /* Node in per-bucket list */
 147 };
 148
 149 struct bgp_bucket {
 150   node send_node;                       /* Node in send queue */
 151   struct bgp_bucket *hash_next, *hash_prev;     /* Node in bucket hash table */
 152   unsigned hash;                        /* Hash over extended attributes */
 153   list prefixes;                        /* Prefixes in this buckets */
 154   ea_list eattrs[0];                    /* Per-bucket extended attributes */
 155 };
 156
 157 #define BGP_PORT                179
 158 #define BGP_VERSION             4
 159 #define BGP_HEADER_LENGTH       19
 160 #define BGP_MAX_PACKET_LENGTH   4096
 161 #define BGP_RX_BUFFER_SIZE      4096
 162 #define BGP_TX_BUFFER_SIZE      BGP_MAX_PACKET_LENGTH
 163
 164 extern struct linpool *bgp_linpool;
 165
 166
 167 void bgp_start_timer(struct timer *t, int value);
 168 void bgp_check_config(struct bgp_config *c);
 169 void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len);
 170 void bgp_close_conn(struct bgp_conn *c);
 171 void bgp_update_startup_delay(struct bgp_proto *p);
 172 void bgp_conn_enter_openconfirm_state(struct bgp_conn *conn);
 173 void bgp_conn_enter_established_state(struct bgp_conn *conn);
 174 void bgp_conn_enter_close_state(struct bgp_conn *conn);
 175 void bgp_conn_enter_idle_state(struct bgp_conn *conn);
 176 void bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code);
 177 void bgp_stop(struct bgp_proto *p, unsigned subcode);
 178
 179 struct rte_source *bgp_find_source(struct bgp_proto *p, u32 path_id);
 180 struct rte_source *bgp_get_source(struct bgp_proto *p, u32 path_id);
 181
 182
 183
 184 #ifdef LOCAL_DEBUG
 185 #define BGP_FORCE_DEBUG 1
 186 #else
 187 #define BGP_FORCE_DEBUG 0
 188 #endif
 189 #define BGP_TRACE(flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
 190         log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
 191
 192 #define BGP_TRACE_RL(rl, flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
 193         log_rl(rl, L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
 194
 195
 196 /* attrs.c */
 197
 198 /* Hack: although BA_NEXT_HOP attribute has type EAF_TYPE_IP_ADDRESS, in IPv6
 199  * we store two addesses in it - a global address and a link local address.
 200  */
 201 #ifdef IPV6
 202 #define NEXT_HOP_LENGTH (2*sizeof(ip_addr))
 203 static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; ((ip_addr *) b)[1] = IPA_NONE; }
 204 #else
 205 #define NEXT_HOP_LENGTH sizeof(ip_addr)
 206 static inline void set_next_hop(byte *b, ip_addr addr) { ((ip_addr *) b)[0] = addr; }
 207 #endif
 208
 209 void bgp_attach_attr(struct ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val);
 210 byte *bgp_attach_attr_wa(struct ea_list **to, struct linpool *pool, unsigned attr, unsigned len);
 211 struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool, int mandatory);
 212 int bgp_get_attr(struct eattr *e, byte *buf, int buflen);
 213 int bgp_rte_better(struct rte *, struct rte *);
 214 int bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best);
 215 void bgp_rt_notify(struct proto *P, rtable *tbl UNUSED, net *n, rte *new, rte *old UNUSED, ea_list *attrs);
 216 int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
 217 void bgp_init_bucket_table(struct bgp_proto *);
 218 void bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck);
 219 void bgp_init_prefix_table(struct bgp_proto *p, u32 order);
 220 void bgp_free_prefix(struct bgp_proto *p, struct bgp_prefix *bp);
 221 unsigned int bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains);
 222 void bgp_get_route_info(struct rte *, byte *buf, struct ea_list *attrs);
 223
 224 inline static void bgp_attach_attr_ip(struct ea_list **to, struct linpool *pool, unsigned attr, ip_addr a)
 225 { *(ip_addr *) bgp_attach_attr_wa(to, pool, attr, sizeof(ip_addr)) = a; }
 226
 227 /* packets.c */
 228
 229 void mrt_dump_bgp_state_change(struct bgp_conn *conn, unsigned old, unsigned new);
 230 void bgp_schedule_packet(struct bgp_conn *conn, int type);
 231 void bgp_kick_tx(void *vconn);
 232 void bgp_tx(struct birdsock *sk);
 233 int bgp_rx(struct birdsock *sk, int size);
 234 const char * bgp_error_dsc(unsigned code, unsigned subcode);
 235 void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len);
 236
 237 /* Packet types */
 238
 239 #define PKT_OPEN                0x01
 240 #define PKT_UPDATE              0x02
 241 #define PKT_NOTIFICATION        0x03
 242 #define PKT_KEEPALIVE           0x04
 243 #define PKT_ROUTE_REFRESH       0x05
 244 #define PKT_SCHEDULE_CLOSE      0x1f    /* Used internally to schedule socket close */
 245
 246 /* Attributes */
 247
 248 #define BAF_OPTIONAL            0x80
 249 #define BAF_TRANSITIVE          0x40
 250 #define BAF_PARTIAL             0x20
 251 #define BAF_EXT_LEN             0x10
 252
 253 #define BA_ORIGIN               0x01    /* [RFC1771] */         /* WM */
 254 #define BA_AS_PATH              0x02                            /* WM */
 255 #define BA_NEXT_HOP             0x03                            /* WM */
 256 #define BA_MULTI_EXIT_DISC      0x04                            /* ON */
 257 #define BA_LOCAL_PREF           0x05                            /* WD */
 258 #define BA_ATOMIC_AGGR          0x06                            /* WD */
 259 #define BA_AGGREGATOR           0x07                            /* OT */
 260 #define BA_COMMUNITY            0x08    /* [RFC1997] */         /* OT */
 261 #define BA_ORIGINATOR_ID        0x09    /* [RFC1966] */         /* ON */
 262 #define BA_CLUSTER_LIST         0x0a                            /* ON */
 263 /* We don't support these: */
 264 #define BA_DPA                  0x0b    /* ??? */
 265 #define BA_ADVERTISER           0x0c    /* [RFC1863] */
 266 #define BA_RCID_PATH            0x0d
 267 #define BA_MP_REACH_NLRI        0x0e    /* [RFC2283] */
 268 #define BA_MP_UNREACH_NLRI      0x0f
 269 #define BA_EXT_COMMUNITY        0x10    /* [RFC4360] */
 270 #define BA_AS4_PATH             0x11    /* [RFC4893] */
 271 #define BA_AS4_AGGREGATOR       0x12
 272
 273 /* BGP connection states */
 274
 275 #define BS_IDLE                 0
 276 #define BS_CONNECT              1       /* Attempting to connect */
 277 #define BS_ACTIVE               2       /* Waiting for connection retry & listening */
 278 #define BS_OPENSENT             3
 279 #define BS_OPENCONFIRM          4
 280 #define BS_ESTABLISHED          5
 281 #define BS_CLOSE                6       /* Used during transition to BS_IDLE */
 282
 283 #define BS_MAX                  7
 284
 285 /* BGP start states
 286  *
 287  * Used in PS_START for fine-grained specification of starting state.
 288  *
 289  * When BGP protocol is started by core, it goes to BSS_PREPARE. When BGP protocol
 290  * done what is neccessary to start itself (like acquiring the lock), it goes to BSS_CONNECT.
 291  * When some connection attempt failed because of option or capability error, it goes to
 292  * BSS_CONNECT_NOCAP.
 293  */
 294
 295 #define BSS_PREPARE             0       /* Used before ordinary BGP started, i. e. waiting for lock */
 296 #define BSS_DELAY               1       /* Startup delay due to previous errors */
 297 #define BSS_CONNECT             2       /* Ordinary BGP connecting */
 298 #define BSS_CONNECT_NOCAP       3       /* Legacy BGP connecting (without capabilities) */
 299
 300 /* Error classes */
 301
 302 #define BE_NONE                 0
 303 #define BE_MISC                 1       /* Miscellaneous error */
 304 #define BE_SOCKET               2       /* Socket error */
 305 #define BE_BGP_RX               3       /* BGP protocol error notification received */
 306 #define BE_BGP_TX               4       /* BGP protocol error notification sent */
 307 #define BE_AUTO_DOWN            5       /* Automatic shutdown */
 308 #define BE_MAN_DOWN             6       /* Manual shutdown */
 309
 310 /* Misc error codes */
 311
 312 #define BEM_NEIGHBOR_LOST       1
 313 #define BEM_INVALID_NEXT_HOP    2
 314 #define BEM_INVALID_MD5         3       /* MD5 authentication kernel request failed (possibly not supported) */
 315 #define BEM_NO_SOCKET           4
 316 #define BEM_BFD_DOWN            5
 317
 318 /* Automatic shutdown error codes */
 319
 320 #define BEA_ROUTE_LIMIT_EXCEEDED 1
 321
 322 /* Well-known communities */
 323
 324 #define BGP_COMM_NO_EXPORT              0xffffff01      /* Don't export outside local AS / confed. */
 325 #define BGP_COMM_NO_ADVERTISE           0xffffff02      /* Don't export at all */
 326 #define BGP_COMM_NO_EXPORT_SUBCONFED    0xffffff03      /* NO_EXPORT even in local confederation */
 327
 328 /* Origins */
 329
 330 #define ORIGIN_IGP              0
 331 #define ORIGIN_EGP              1
 332 #define ORIGIN_INCOMPLETE       2
 333
 334 /* Address families */
 335
 336 #define BGP_AF_IPV4             1
 337 #define BGP_AF_IPV6             2
 338
 339 #ifdef IPV6
 340 #define BGP_AF BGP_AF_IPV6
 341 #else
 342 #define BGP_AF BGP_AF_IPV4
 343 #endif
 344
 345 #endif