bgpd/bgp_attr.h

   1 /* BGP attributes.
   2    Copyright (C) 1996, 97, 98 Kunihiro Ishiguro
   3
   4 This file is part of GNU Zebra.
   5
   6 GNU Zebra is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 2, or (at your option) any
   9 later version.
  10
  11 GNU Zebra is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Zebra; see the file COPYING.  If not, write to the Free
  18 Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #ifndef _QUAGGA_BGP_ATTR_H
  22 #define _QUAGGA_BGP_ATTR_H
  23
  24 /* Simple bit mapping. */
  25 #define BITMAP_NBBY 8
  26
  27 #define SET_BITMAP(MAP, NUM) \
  28         SET_FLAG (MAP[(NUM) / BITMAP_NBBY], 1 << ((NUM) % BITMAP_NBBY))
  29
  30 #define CHECK_BITMAP(MAP, NUM) \
  31         CHECK_FLAG (MAP[(NUM) / BITMAP_NBBY], 1 << ((NUM) % BITMAP_NBBY))
  32
  33 #define BGP_MED_MAX UINT32_MAX
  34
  35
  36 /* BGP Attribute type range. */
  37 #define BGP_ATTR_TYPE_RANGE     256
  38 #define BGP_ATTR_BITMAP_SIZE    (BGP_ATTR_TYPE_RANGE / BITMAP_NBBY)
  39
  40 /* BGP Attribute flags. */
  41 #define BGP_ATTR_FLAG_OPTIONAL  0x80    /* Attribute is optional. */
  42 #define BGP_ATTR_FLAG_TRANS     0x40    /* Attribute is transitive. */
  43 #define BGP_ATTR_FLAG_PARTIAL   0x20    /* Attribute is partial. */
  44 #define BGP_ATTR_FLAG_EXTLEN    0x10    /* Extended length flag. */
  45
  46 /* BGP attribute header must bigger than 2. */
  47 #define BGP_ATTR_MIN_LEN        3       /* Attribute flag, type length. */
  48 #define BGP_ATTR_DEFAULT_WEIGHT 32768
  49
  50 /* Valid lengths for mp_nexthop_len */
  51 #define BGP_ATTR_NHLEN_IPV4               IPV4_MAX_BYTELEN
  52 #define BGP_ATTR_NHLEN_VPNV4              12
  53 #define BGP_ATTR_NHLEN_IPV6_GLOBAL        IPV6_MAX_BYTELEN
  54 #define BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL (IPV6_MAX_BYTELEN * 2)
  55
  56 /* Additional/uncommon BGP attributes.
  57  * lazily allocated as and when a struct attr
  58  * requires it.
  59  */
  60 struct attr_extra
  61 {
  62   /* Multi-Protocol Nexthop, AFI IPv6 */
  63   struct in6_addr mp_nexthop_global;
  64   struct in6_addr mp_nexthop_local;
  65
  66   /* Extended Communities attribute. */
  67   struct ecommunity *ecommunity;
  68
  69   /* Route-Reflector Cluster attribute */
  70   struct cluster_list *cluster;
  71
  72   /* Unknown transitive attribute. */
  73   struct transit *transit;
  74
  75   struct in_addr mp_nexthop_global_in;
  76
  77   /* Aggregator Router ID attribute */
  78   struct in_addr aggregator_addr;
  79
  80   /* Route Reflector Originator attribute */
  81   struct in_addr originator_id;
  82
  83   /* Local weight, not actually an attribute */
  84   u_int32_t weight;
  85
  86   /* Aggregator ASN */
  87   as_t aggregator_as;
  88
  89   /* MP Nexthop length */
  90   u_char mp_nexthop_len;
  91
  92   /* route tag */
  93   u_short tag;
  94 };
  95
  96 /* BGP core attribute structure. */
  97 struct attr
  98 {
  99   /* AS Path structure */
 100   struct aspath *aspath;
 101
 102   /* Community structure */
 103   struct community *community;
 104
 105   /* Lazily allocated pointer to extra attributes */
 106   struct attr_extra *extra;
 107
 108   /* Reference count of this attribute. */
 109   unsigned long refcnt;
 110
 111   /* Flag of attribute is set or not. */
 112   u_int32_t flag;
 113
 114   /* Apart from in6_addr, the remaining static attributes */
 115   struct in_addr nexthop;
 116   u_int32_t med;
 117   u_int32_t local_pref;
 118   u_int32_t nh_ifindex;
 119
 120   /* Path origin attribute */
 121   u_char origin;
 122
 123   /* has the route-map changed any attribute?
 124      Used on the peer outbound side. */
 125   u_int32_t rmap_change_flags;
 126 };
 127
 128 /* rmap_change_flags definition */
 129 #define BATTR_RMAP_IPV4_NHOP_CHANGED (1 << 0)
 130 #define BATTR_RMAP_NEXTHOP_PEER_ADDRESS (1 << 1)
 131 #define BATTR_REFLECTED (1 << 2)
 132 #define BATTR_RMAP_NEXTHOP_UNCHANGED (1 << 3)
 133 #define BATTR_RMAP_IPV6_GLOBAL_NHOP_CHANGED (1 << 4)
 134 #define BATTR_RMAP_IPV6_LL_NHOP_CHANGED (1 << 5)
 135
 136 /* Router Reflector related structure. */
 137 struct cluster_list
 138 {
 139   unsigned long refcnt;
 140   int length;
 141   struct in_addr *list;
 142 };
 143
 144 /* Unknown transit attribute. */
 145 struct transit
 146 {
 147   unsigned long refcnt;
 148   int length;
 149   u_char *val;
 150 };
 151
 152 #define ATTR_FLAG_BIT(X)  (1 << ((X) - 1))
 153
 154 #define BGP_CLUSTER_LIST_LENGTH(attr)                           \
 155   (((attr)->flag & ATTR_FLAG_BIT(BGP_ATTR_CLUSTER_LIST)) ?      \
 156    (attr)->extra->cluster->length : 0)
 157
 158 typedef enum {
 159  BGP_ATTR_PARSE_PROCEED = 0,
 160  BGP_ATTR_PARSE_ERROR = -1,
 161  BGP_ATTR_PARSE_WITHDRAW = -2,
 162
 163  /* only used internally, send notify + convert to BGP_ATTR_PARSE_ERROR */
 164  BGP_ATTR_PARSE_ERROR_NOTIFYPLS = -3,
 165 } bgp_attr_parse_ret_t;
 166
 167 struct bpacket_attr_vec_arr;
 168
 169 /* Prototypes. */
 170 extern void bgp_attr_init (void);
 171 extern void bgp_attr_finish (void);
 172 extern bgp_attr_parse_ret_t bgp_attr_parse (struct peer *, struct attr *,
 173                                            bgp_size_t, struct bgp_nlri *,
 174                                            struct bgp_nlri *);
 175 extern int bgp_attr_check (struct peer *, struct attr *, bgp_size_t);
 176 extern struct attr_extra *bgp_attr_extra_get (struct attr *);
 177 extern void bgp_attr_extra_free (struct attr *);
 178 extern void bgp_attr_dup (struct attr *, struct attr *);
 179 extern void bgp_attr_deep_dup (struct attr *, struct attr *);
 180 extern void bgp_attr_deep_free (struct attr *);
 181 extern struct attr *bgp_attr_intern (struct attr *attr);
 182 extern struct attr *bgp_attr_refcount (struct attr *attr);
 183 extern void bgp_attr_unintern_sub (struct attr *);
 184 extern void bgp_attr_unintern (struct attr **);
 185 extern void bgp_attr_flush (struct attr *);
 186 extern struct attr *bgp_attr_default_set (struct attr *attr, u_char);
 187 extern struct attr *bgp_attr_default_intern (u_char);
 188 extern struct attr *bgp_attr_aggregate_intern (struct bgp *, u_char,
 189                                         struct aspath *,
 190                                         struct community *, int as_set, u_char);
 191 extern bgp_size_t bgp_packet_attribute (struct bgp *bgp, struct peer *,
 192                                         struct stream *, struct attr *,
 193                                         struct bpacket_attr_vec_arr *vecarr,
 194                                         struct prefix *, afi_t, safi_t,
 195                                         struct peer *, struct prefix_rd *,
 196                                         u_char *, int, u_int32_t);
 197 extern void bgp_dump_routes_attr (struct stream *, struct attr *,
 198                                   struct prefix *);
 199 extern int attrhash_cmp (const void *, const void *);
 200 extern unsigned int attrhash_key_make (void *);
 201 extern void attr_show_all (struct vty *);
 202 extern unsigned long int attr_count (void);
 203 extern unsigned long int attr_unknown_count (void);
 204
 205 /* Cluster list prototypes. */
 206 extern int cluster_loop_check (struct cluster_list *, struct in_addr);
 207 extern void cluster_unintern (struct cluster_list *);
 208
 209 /* Transit attribute prototypes. */
 210 void transit_unintern (struct transit *);
 211
 212 /* Below exported for unit-test purposes only */
 213 struct bgp_attr_parser_args {
 214   struct peer *peer;
 215   bgp_size_t length; /* attribute data length; */
 216   bgp_size_t total; /* total length, inc header */
 217   struct attr *attr;
 218   u_int8_t type;
 219   u_int8_t flags;
 220   u_char *startp;
 221 };
 222 extern int bgp_mp_reach_parse (struct bgp_attr_parser_args *args,
 223                                struct bgp_nlri *);
 224 extern int bgp_mp_unreach_parse (struct bgp_attr_parser_args *args,
 225                                  struct bgp_nlri *);
 226
 227 /**
 228  * Set of functions to encode MP_REACH_NLRI and MP_UNREACH_NLRI attributes.
 229  * Typical call sequence is to call _start(), followed by multiple _prefix(),
 230  * one for each NLRI that needs to be encoded into the UPDATE message, and
 231  * finally the _end() function.
 232  */
 233 extern size_t bgp_packet_mpattr_start(struct stream *s, afi_t afi, safi_t safi,
 234                                       afi_t nh_afi,
 235                                       struct bpacket_attr_vec_arr *vecarr,
 236                                       struct attr *attr);
 237 extern void bgp_packet_mpattr_prefix(struct stream *s, afi_t afi, safi_t safi,
 238                                      struct prefix *p, struct prefix_rd *prd,
 239                                      u_char *tag, int addpath_encode,
 240                                      u_int32_t addpath_tx_id);
 241 extern void bgp_packet_mpattr_end(struct stream *s, size_t sizep);
 242
 243 extern size_t bgp_packet_mpunreach_start (struct stream *s, afi_t afi,
 244                                           safi_t safi);
 245 extern void bgp_packet_mpunreach_prefix (struct stream *s, struct prefix *p,
 246                              afi_t afi, safi_t safi, struct prefix_rd *prd,
 247                              u_char *tag, int, u_int32_t);
 248 extern void bgp_packet_mpunreach_end (struct stream *s, size_t attrlen_pnt);
 249
 250 static inline int
 251 bgp_rmap_nhop_changed(u_int32_t out_rmap_flags, u_int32_t in_rmap_flags)
 252 {
 253   return ((CHECK_FLAG(out_rmap_flags, BATTR_RMAP_NEXTHOP_PEER_ADDRESS) ||
 254            CHECK_FLAG(out_rmap_flags, BATTR_RMAP_NEXTHOP_UNCHANGED) ||
 255            CHECK_FLAG(out_rmap_flags, BATTR_RMAP_IPV4_NHOP_CHANGED) ||
 256            CHECK_FLAG(out_rmap_flags, BATTR_RMAP_IPV6_GLOBAL_NHOP_CHANGED) ||
 257            CHECK_FLAG(out_rmap_flags, BATTR_RMAP_IPV6_LL_NHOP_CHANGED) ||
 258            CHECK_FLAG(in_rmap_flags, BATTR_RMAP_NEXTHOP_UNCHANGED)) ? 1 : 0);
 259 }
 260
 261 #endif /* _QUAGGA_BGP_ATTR_H */