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 "nest/route.h"
  13
  14 struct linpool;
  15 struct eattr;
  16
  17 struct bgp_config {
  18   struct proto_config c;
  19   u32 local_as, remote_as;
  20   ip_addr remote_ip;
  21   int multihop;                         /* Number of hops if multihop */
  22   ip_addr multihop_via;                 /* Multihop: address to route to */
  23   ip_addr source_addr;                  /* Source address to use */
  24   int next_hop_self;                    /* Always set next hop to local IP address */
  25   int compare_path_lengths;             /* Use path lengths when selecting best route */
  26   u32 default_local_pref;               /* Default value for LOCAL_PREF attribute */
  27   u32 default_med;                      /* Default value for MULTI_EXIT_DISC attribute */
  28   unsigned connect_retry_time;
  29   unsigned hold_time, initial_hold_time;
  30   unsigned keepalive_time;
  31   unsigned start_delay_time;            /* Minimum delay between connects */
  32   unsigned error_amnesia_time;          /* Errors are forgotten after */
  33   unsigned error_delay_time_min;        /* Time to wait after an error is detected */
  34   unsigned error_delay_time_max;
  35   unsigned disable_after_error;         /* Disable the protocol when error is detected */
  36 };
  37
  38 struct bgp_conn {
  39   struct bgp_proto *bgp;
  40   struct birdsock *sk;
  41   unsigned int state;                   /* State of connection state machine */
  42   struct timer *connect_retry_timer;
  43   struct timer *hold_timer;
  44   struct timer *keepalive_timer;
  45   int packets_to_send;                  /* Bitmap of packet types to be sent */
  46   int notify_code, notify_subcode, notify_size;
  47   byte *notify_data;
  48   int error_flag;                       /* Error state, ignore all input */
  49   int primary;                          /* This connection is primary */
  50   u32 advertised_as;                    /* Temporary value for AS number received */
  51   unsigned hold_time, keepalive_time;   /* Times calculated from my and neighbor's requirements */
  52 };
  53
  54 struct bgp_proto {
  55   struct proto p;
  56   struct bgp_config *cf;                /* Shortcut to BGP configuration */
  57   u32 local_as, remote_as;
  58   int is_internal;                      /* Internal BGP connection (local_as == remote_as) */
  59   int as4_support;                      /* Peer supports 4B AS numbers [RFC4893] */
  60   u32 local_id;                         /* BGP identifier of this router */
  61   u32 remote_id;                        /* BGP identifier of the neighbor */
  62   struct bgp_conn *conn;                /* Connection we have established */
  63   struct bgp_conn outgoing_conn;        /* Outgoing connection we're working with */
  64   struct bgp_conn incoming_conn;        /* Incoming connection we have neither accepted nor rejected yet */
  65   struct object_lock *lock;             /* Lock for neighbor connection */
  66   ip_addr next_hop;                     /* Either the peer or multihop_via */
  67   struct neighbor *neigh;               /* Neighbor entry corresponding to next_hop */
  68   ip_addr local_addr;                   /* Address of the local end of the link to next_hop */
  69   struct bgp_bucket **bucket_hash;      /* Hash table of attribute buckets */
  70   unsigned int hash_size, hash_count, hash_limit;
  71   struct fib prefix_fib;                /* Prefixes to be sent */
  72   list bucket_queue;                    /* Queue of buckets to send */
  73   struct bgp_bucket *withdraw_bucket;   /* Withdrawn routes */
  74   unsigned startup_delay;               /* Time to delay protocol startup by due to errors */
  75   bird_clock_t last_connect;            /* Time of last connect attempt */
  76 #ifdef IPV6
  77   byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute notes */
  78   unsigned mp_reach_len, mp_unreach_len;
  79   ip_addr local_link;                   /* Link-level version of local_addr */
  80 #endif
  81 };
  82
  83 struct bgp_prefix {
  84   struct fib_node n;                    /* Node in prefix fib */
  85   node bucket_node;                     /* Node in per-bucket list */
  86 };
  87
  88 struct bgp_bucket {
  89   node send_node;                       /* Node in send queue */
  90   struct bgp_bucket *hash_next, *hash_prev;     /* Node in bucket hash table */
  91   unsigned hash;                        /* Hash over extended attributes */
  92   list prefixes;                        /* Prefixes in this buckets */
  93   ea_list eattrs[0];                    /* Per-bucket extended attributes */
  94 };
  95
  96 #define BGP_PORT                179
  97 #define BGP_VERSION             4
  98 #define BGP_HEADER_LENGTH       19
  99 #define BGP_MAX_PACKET_LENGTH   4096
 100 #define BGP_RX_BUFFER_SIZE      4096
 101 #define BGP_TX_BUFFER_SIZE      BGP_MAX_PACKET_LENGTH
 102
 103 extern struct linpool *bgp_linpool;
 104
 105 extern int bgp_as4_support;
 106
 107
 108 void bgp_start_timer(struct timer *t, int value);
 109 void bgp_check(struct bgp_config *c);
 110 void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len);
 111 void bgp_close_conn(struct bgp_conn *c);
 112
 113 #ifdef LOCAL_DEBUG
 114 #define BGP_FORCE_DEBUG 1
 115 #else
 116 #define BGP_FORCE_DEBUG 0
 117 #endif
 118 #define BGP_TRACE(flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
 119         log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
 120
 121 /* attrs.c */
 122
 123 byte *bgp_attach_attr(struct ea_list **to, struct linpool *, unsigned attr, unsigned val);
 124 struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool, int mandatory);
 125 int bgp_get_attr(struct eattr *e, byte *buf);
 126 int bgp_rte_better(struct rte *, struct rte *);
 127 void bgp_rt_notify(struct proto *, struct network *, struct rte *, struct rte *, struct ea_list *);
 128 int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
 129 void bgp_attr_init(struct bgp_proto *);
 130 unsigned int bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains);
 131 void bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck);
 132 void bgp_get_route_info(struct rte *, byte *buf, struct ea_list *attrs);
 133
 134 /* packets.c */
 135
 136 void bgp_schedule_packet(struct bgp_conn *conn, int type);
 137 void bgp_tx(struct birdsock *sk);
 138 int bgp_rx(struct birdsock *sk, int size);
 139 void bgp_log_error(struct bgp_proto *p, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len);
 140
 141 /* Packet types */
 142
 143 #define PKT_OPEN                0x01
 144 #define PKT_UPDATE              0x02
 145 #define PKT_NOTIFICATION        0x03
 146 #define PKT_KEEPALIVE           0x04
 147 #define PKT_SCHEDULE_CLOSE      0x1f    /* Used internally to schedule socket close */
 148
 149 /* Attributes */
 150
 151 #define BAF_OPTIONAL            0x80
 152 #define BAF_TRANSITIVE          0x40
 153 #define BAF_PARTIAL             0x20
 154 #define BAF_EXT_LEN             0x10
 155
 156 #define BA_ORIGIN               0x01    /* [RFC1771] */         /* WM */
 157 #define BA_AS_PATH              0x02                            /* WM */
 158 #define BA_NEXT_HOP             0x03                            /* WM */
 159 #define BA_MULTI_EXIT_DISC      0x04                            /* ON */
 160 #define BA_LOCAL_PREF           0x05                            /* WD */
 161 #define BA_ATOMIC_AGGR          0x06                            /* WD */
 162 #define BA_AGGREGATOR           0x07                            /* OT */
 163 #define BA_COMMUNITY            0x08    /* [RFC1997] */         /* OT */
 164 #define BA_ORIGINATOR_ID        0x09    /* [RFC1966] */         /* ON */
 165 #define BA_CLUSTER_LIST         0x0a                            /* ON */
 166 /* We don't support these: */
 167 #define BA_DPA                  0x0b    /* ??? */
 168 #define BA_ADVERTISER           0x0c    /* [RFC1863] */
 169 #define BA_RCID_PATH            0x0d
 170 #define BA_MP_REACH_NLRI        0x0e    /* [RFC2283] */
 171 #define BA_MP_UNREACH_NLRI      0x0f
 172 #define BA_EXTENDED_COMM        0x10    /* draft-ramachandra-bgp-ext-communities */
 173 #define BA_AS4_PATH             0x11    /* [RFC4893] */
 174 #define BA_AS4_AGGREGATOR       0x12
 175
 176 /* BGP states */
 177
 178 #define BS_IDLE                 0
 179 #define BS_CONNECT              1       /* Attempting to connect */
 180 #define BS_ACTIVE               2       /* Waiting for connection retry & listening */
 181 #define BS_OPENSENT             3
 182 #define BS_OPENCONFIRM          4
 183 #define BS_ESTABLISHED          5
 184
 185 /* Well-known communities */
 186
 187 #define BGP_COMM_NO_EXPORT              0xffffff01      /* Don't export outside local AS / confed. */
 188 #define BGP_COMM_NO_ADVERTISE           0xffffff02      /* Don't export at all */
 189 #define BGP_COMM_NO_EXPORT_SUBCONFED    0xffffff03      /* NO_EXPORT even in local confederation */
 190
 191 /* Origins */
 192
 193 #define ORIGIN_IGP              0
 194 #define ORIGIN_EGP              1
 195 #define ORIGIN_INCOMPLETE       2
 196
 197 /* Address families */
 198
 199 #define BGP_AF_IPV6             2
 200
 201 #endif