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   int enable_as4;                       /* Enable local support for 4B AS numbers [RFC4893] */
  29   u32 rr_cluster_id;                    /* Route reflector cluster ID, if different from local ID */
  30   int rr_client;                        /* Whether neighbor is RR client of me */
  31   int rs_client;                        /* Whether neighbor is RS client of me */
  32   unsigned connect_retry_time;
  33   unsigned hold_time, initial_hold_time;
  34   unsigned keepalive_time;
  35   unsigned start_delay_time;            /* Minimum delay between connects */
  36   unsigned error_amnesia_time;          /* Errors are forgotten after */
  37   unsigned error_delay_time_min;        /* Time to wait after an error is detected */
  38   unsigned error_delay_time_max;
  39   unsigned disable_after_error;         /* Disable the protocol when error is detected */
  40   char *password;                       /* Password used for MD5 authentication */
  41 };
  42
  43 struct bgp_conn {
  44   struct bgp_proto *bgp;
  45   struct birdsock *sk;
  46   unsigned int state;                   /* State of connection state machine */
  47   struct timer *connect_retry_timer;
  48   struct timer *hold_timer;
  49   struct timer *keepalive_timer;
  50   int packets_to_send;                  /* Bitmap of packet types to be sent */
  51   int notify_code, notify_subcode, notify_size;
  52   byte *notify_data;
  53   int error_flag;                       /* Error state, ignore all input */
  54   int primary;                          /* This connection is primary */
  55   u32 advertised_as;                    /* Temporary value for AS number received */
  56   unsigned hold_time, keepalive_time;   /* Times calculated from my and neighbor's requirements */
  57 };
  58
  59 struct bgp_proto {
  60   struct proto p;
  61   struct bgp_config *cf;                /* Shortcut to BGP configuration */
  62   u32 local_as, remote_as;
  63   int is_internal;                      /* Internal BGP connection (local_as == remote_as) */
  64   int as4_support;                      /* Peer supports 4B AS numbers [RFC4893] */
  65   int as4_session;                      /* Session uses 4B AS numbers in AS_PATH (both sides support it) */
  66   u32 local_id;                         /* BGP identifier of this router */
  67   u32 remote_id;                        /* BGP identifier of the neighbor */
  68   u32 rr_cluster_id;                    /* Route reflector cluster ID */
  69   int rr_client;                        /* Whether neighbor is RR client of me */
  70   int rs_client;                        /* Whether neighbor is RS client of me */
  71   struct bgp_conn *conn;                /* Connection we have established */
  72   struct bgp_conn outgoing_conn;        /* Outgoing connection we're working with */
  73   struct bgp_conn incoming_conn;        /* Incoming connection we have neither accepted nor rejected yet */
  74   struct object_lock *lock;             /* Lock for neighbor connection */
  75   ip_addr next_hop;                     /* Either the peer or multihop_via */
  76   struct neighbor *neigh;               /* Neighbor entry corresponding to next_hop */
  77   ip_addr local_addr;                   /* Address of the local end of the link to next_hop */
  78   struct bgp_bucket **bucket_hash;      /* Hash table of attribute buckets */
  79   unsigned int hash_size, hash_count, hash_limit;
  80   struct fib prefix_fib;                /* Prefixes to be sent */
  81   list bucket_queue;                    /* Queue of buckets to send */
  82   struct bgp_bucket *withdraw_bucket;   /* Withdrawn routes */
  83   unsigned startup_delay;               /* Time to delay protocol startup by due to errors */
  84   bird_clock_t last_connect;            /* Time of last connect attempt */
  85 #ifdef IPV6
  86   byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute notes */
  87   unsigned mp_reach_len, mp_unreach_len;
  88   ip_addr local_link;                   /* Link-level version of local_addr */
  89 #endif
  90 };
  91
  92 struct bgp_prefix {
  93   struct fib_node n;                    /* Node in prefix fib */
  94   node bucket_node;                     /* Node in per-bucket list */
  95 };
  96
  97 struct bgp_bucket {
  98   node send_node;                       /* Node in send queue */
  99   struct bgp_bucket *hash_next, *hash_prev;     /* Node in bucket hash table */
 100   unsigned hash;                        /* Hash over extended attributes */
 101   list prefixes;                        /* Prefixes in this buckets */
 102   ea_list eattrs[0];                    /* Per-bucket extended attributes */
 103 };
 104
 105 #define BGP_PORT                179
 106 #define BGP_VERSION             4
 107 #define BGP_HEADER_LENGTH       19
 108 #define BGP_MAX_PACKET_LENGTH   4096
 109 #define BGP_RX_BUFFER_SIZE      4096
 110 #define BGP_TX_BUFFER_SIZE      BGP_MAX_PACKET_LENGTH
 111
 112 extern struct linpool *bgp_linpool;
 113
 114 extern int bgp_as4_support;
 115
 116
 117 void bgp_start_timer(struct timer *t, int value);
 118 void bgp_check(struct bgp_config *c);
 119 void bgp_error(struct bgp_conn *c, unsigned code, unsigned subcode, byte *data, int len);
 120 void bgp_close_conn(struct bgp_conn *c);
 121
 122 #ifdef LOCAL_DEBUG
 123 #define BGP_FORCE_DEBUG 1
 124 #else
 125 #define BGP_FORCE_DEBUG 0
 126 #endif
 127 #define BGP_TRACE(flags, msg, args...) do { if ((p->p.debug & flags) || BGP_FORCE_DEBUG) \
 128         log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
 129
 130 /* attrs.c */
 131
 132 void bgp_attach_attr(struct ea_list **to, struct linpool *pool, unsigned attr, uintptr_t val);
 133 byte *bgp_attach_attr_wa(struct ea_list **to, struct linpool *pool, unsigned attr, unsigned len);
 134 struct rta *bgp_decode_attrs(struct bgp_conn *conn, byte *a, unsigned int len, struct linpool *pool, int mandatory);
 135 int bgp_get_attr(struct eattr *e, byte *buf, int buflen);
 136 int bgp_rte_better(struct rte *, struct rte *);
 137 void bgp_rt_notify(struct proto *, struct network *, struct rte *, struct rte *, struct ea_list *);
 138 int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
 139 void bgp_attr_init(struct bgp_proto *);
 140 unsigned int bgp_encode_attrs(struct bgp_proto *p, byte *w, ea_list *attrs, int remains);
 141 void bgp_free_bucket(struct bgp_proto *p, struct bgp_bucket *buck);
 142 void bgp_get_route_info(struct rte *, byte *buf, struct ea_list *attrs);
 143
 144 inline static void bgp_attach_attr_ip(struct ea_list **to, struct linpool *pool, unsigned attr, ip_addr a)
 145 { *(ip_addr *) bgp_attach_attr_wa(to, pool, attr, sizeof(ip_addr)) = a; }
 146
 147 /* packets.c */
 148
 149 void bgp_schedule_packet(struct bgp_conn *conn, int type);
 150 void bgp_tx(struct birdsock *sk);
 151 int bgp_rx(struct birdsock *sk, int size);
 152 void bgp_log_error(struct bgp_proto *p, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len);
 153
 154 /* Packet types */
 155
 156 #define PKT_OPEN                0x01
 157 #define PKT_UPDATE              0x02
 158 #define PKT_NOTIFICATION        0x03
 159 #define PKT_KEEPALIVE           0x04
 160 #define PKT_SCHEDULE_CLOSE      0x1f    /* Used internally to schedule socket close */
 161
 162 /* Attributes */
 163
 164 #define BAF_OPTIONAL            0x80
 165 #define BAF_TRANSITIVE          0x40
 166 #define BAF_PARTIAL             0x20
 167 #define BAF_EXT_LEN             0x10
 168
 169 #define BA_ORIGIN               0x01    /* [RFC1771] */         /* WM */
 170 #define BA_AS_PATH              0x02                            /* WM */
 171 #define BA_NEXT_HOP             0x03                            /* WM */
 172 #define BA_MULTI_EXIT_DISC      0x04                            /* ON */
 173 #define BA_LOCAL_PREF           0x05                            /* WD */
 174 #define BA_ATOMIC_AGGR          0x06                            /* WD */
 175 #define BA_AGGREGATOR           0x07                            /* OT */
 176 #define BA_COMMUNITY            0x08    /* [RFC1997] */         /* OT */
 177 #define BA_ORIGINATOR_ID        0x09    /* [RFC1966] */         /* ON */
 178 #define BA_CLUSTER_LIST         0x0a                            /* ON */
 179 /* We don't support these: */
 180 #define BA_DPA                  0x0b    /* ??? */
 181 #define BA_ADVERTISER           0x0c    /* [RFC1863] */
 182 #define BA_RCID_PATH            0x0d
 183 #define BA_MP_REACH_NLRI        0x0e    /* [RFC2283] */
 184 #define BA_MP_UNREACH_NLRI      0x0f
 185 #define BA_EXTENDED_COMM        0x10    /* draft-ramachandra-bgp-ext-communities */
 186 #define BA_AS4_PATH             0x11    /* [RFC4893] */
 187 #define BA_AS4_AGGREGATOR       0x12
 188
 189 /* BGP states */
 190
 191 #define BS_IDLE                 0
 192 #define BS_CONNECT              1       /* Attempting to connect */
 193 #define BS_ACTIVE               2       /* Waiting for connection retry & listening */
 194 #define BS_OPENSENT             3
 195 #define BS_OPENCONFIRM          4
 196 #define BS_ESTABLISHED          5
 197
 198 /* Well-known communities */
 199
 200 #define BGP_COMM_NO_EXPORT              0xffffff01      /* Don't export outside local AS / confed. */
 201 #define BGP_COMM_NO_ADVERTISE           0xffffff02      /* Don't export at all */
 202 #define BGP_COMM_NO_EXPORT_SUBCONFED    0xffffff03      /* NO_EXPORT even in local confederation */
 203
 204 /* Origins */
 205
 206 #define ORIGIN_IGP              0
 207 #define ORIGIN_EGP              1
 208 #define ORIGIN_INCOMPLETE       2
 209
 210 /* Address families */
 211
 212 #define BGP_AF_IPV6             2
 213
 214 #endif