bgpd/bgp_label.h

   1 /* BGP carrying Label information
   2  * Copyright (C) 2013 Cumulus Networks, Inc.
   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 along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef _BGP_LABEL_H
  22 #define _BGP_LABEL_H
  23
  24 #define BGP_LABEL_BYTES 3
  25 #define BGP_LABEL_BITS 24
  26 #define BGP_WITHDRAW_LABEL 0x800000
  27
  28 struct bgp_node;
  29 struct bgp_info;
  30 struct peer;
  31
  32 extern void bgp_reg_dereg_for_label (struct bgp_node *rn, struct bgp_info *ri,
  33                                      int reg);
  34 extern int bgp_parse_fec_update(void);
  35 extern mpls_label_t bgp_adv_label(struct bgp_node *rn, struct bgp_info *ri,
  36                                   struct peer *to, afi_t afi, safi_t safi);
  37
  38 extern int bgp_nlri_parse_label (struct peer *peer, struct attr *attr,
  39                                  struct bgp_nlri *packet);
  40
  41 static inline int
  42 bgp_labeled_safi (safi_t safi)
  43 {
  44   /* NOTE: This API really says a label (tag) MAY be present. Not all EVPN
  45    * routes will have a label.
  46    */
  47   if ((safi == SAFI_LABELED_UNICAST) || (safi == SAFI_MPLS_VPN) ||
  48       (safi == SAFI_EVPN))
  49     return 1;
  50   return 0;
  51 }
  52
  53 static inline int
  54 bgp_is_withdraw_label (mpls_label_t *label)
  55 {
  56   u_char *pkt = (u_char *) label;
  57
  58   /* The check on pkt[2] for 0x00 or 0x02 is in case bgp_set_valid_label()
  59    * was called on the withdraw label */
  60   if ((pkt[0] == 0x80) && (pkt[1] == 0x00) && ((pkt[2] == 0x00) || (pkt[2] == 0x02)))
  61       return 1;
  62   return 0;
  63 }
  64
  65 static inline int
  66 bgp_is_valid_label (mpls_label_t *label)
  67 {
  68   u_char *t= (u_char *) label;
  69   if (!t)
  70     return 0;
  71   return (t[2] & 0x02);
  72 }
  73
  74 static inline void
  75 bgp_set_valid_label (mpls_label_t *label)
  76 {
  77   u_char *t= (u_char *) label;
  78   if (t)
  79     t[2] |= 0x02;
  80 }
  81
  82 static inline void
  83 bgp_unset_valid_label (mpls_label_t *label)
  84 {
  85   u_char *t= (u_char *) label;
  86   if (t)
  87     t[2] &= ~0x02;
  88 }
  89
  90 static inline void
  91 bgp_register_for_label (struct bgp_node *rn, struct bgp_info *ri)
  92 {
  93   bgp_reg_dereg_for_label (rn, ri, 1);
  94 }
  95
  96 static inline void
  97 bgp_unregister_for_label (struct bgp_node *rn)
  98 {
  99   bgp_reg_dereg_for_label (rn, NULL, 0);
 100 }
 101
 102 /* Label stream to value */
 103 static inline u_int32_t
 104 label_pton (mpls_label_t *label)
 105 {
 106   u_char *t= (u_char *) label;
 107   return ((((unsigned int) t[0]) << 12) | (((unsigned int) t[1]) << 4) |
 108          ((unsigned int) ((t[2] & 0xF0) >> 4)));
 109 }
 110
 111 /* Encode label values */
 112 static inline void
 113 label_ntop (u_int32_t l, int bos, mpls_label_t *label)
 114 {
 115   u_char *t= (u_char *) label;
 116   t[0] = ((l & 0x000FF000) >> 12);
 117   t[1] = ((l & 0x00000FF0) >> 4);
 118   t[2] = ((l & 0x0000000F) << 4);
 119   if (bos)
 120     t[2] |= 0x01;
 121 }
 122
 123 /* Return BOS value of label stream */
 124 static inline u_char
 125 label_bos (mpls_label_t *label)
 126 {
 127   u_char *t= (u_char *) label;
 128   return (t[2] & 0x01);
 129 };
 130
 131 #endif /* _BGP_LABEL_H */