lib/mpls.h

   1 /*
   2  * MPLS definitions
   3  * Copyright 2015 Cumulus Networks, Inc.
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published
   9  * by the Free Software Foundation; either version 2, or (at your
  10  * option) any later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; see the file COPYING; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef _QUAGGA_MPLS_H
  23 #define _QUAGGA_MPLS_H
  24
  25 #include <arpa/inet.h>
  26
  27 /* Well-known MPLS label values (RFC 3032 etc). */
  28 #define MPLS_V4_EXP_NULL_LABEL             0
  29 #define MPLS_RA_LABEL                      1
  30 #define MPLS_V6_EXP_NULL_LABEL             2
  31 #define MPLS_IMP_NULL_LABEL                3
  32 #define MPLS_ENTROPY_LABEL_INDICATOR       7
  33 #define MPLS_GAL_LABEL                     13
  34 #define MPLS_OAM_ALERT_LABEL               14
  35 #define MPLS_EXTENSION_LABEL               15
  36
  37 /* Minimum and maximum label values */
  38 #define MPLS_MIN_RESERVED_LABEL            0
  39 #define MPLS_MAX_RESERVED_LABEL            15
  40 #define MPLS_MIN_UNRESERVED_LABEL          16
  41 #define MPLS_MAX_UNRESERVED_LABEL          1048575
  42
  43 /* Default min and max SRGB label range */
  44 #define MPLS_DEFAULT_MIN_SRGB_LABEL        16000
  45 #define MPLS_DEFAULT_MAX_SRGB_LABEL        23999
  46
  47 #define IS_MPLS_RESERVED_LABEL(label) \
  48         (label >= MPLS_MIN_RESERVED_LABEL && label <= MPLS_MAX_RESERVED_LABEL)
  49
  50 #define IS_MPLS_UNRESERVED_LABEL(label) \
  51         (label >= MPLS_MIN_UNRESERVED_LABEL && label <= MPLS_MAX_UNRESERVED_LABEL)
  52
  53 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  54  * label, EXP, BOS and TTL fields.
  55  */
  56 typedef unsigned int mpls_lse_t;
  57
  58 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  59 #define MPLS_LS_LABEL_SHIFT            12
  60 #define MPLS_LS_EXP_MASK               0x00000E00
  61 #define MPLS_LS_EXP_SHIFT              9
  62 #define MPLS_LS_S_MASK                 0x00000100
  63 #define MPLS_LS_S_SHIFT                8
  64 #define MPLS_LS_TTL_MASK               0x000000FF
  65 #define MPLS_LS_TTL_SHIFT              0
  66
  67 #define MPLS_LABEL_VALUE(lse) \
  68         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  69 #define MPLS_LABEL_EXP(lse) \
  70         ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  71 #define MPLS_LABEL_BOS(lse) \
  72         ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  73 #define MPLS_LABEL_TTL(lse) \
  74         ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  75
  76 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  77
  78 #define MPLS_LABEL_LEN_BITS            20
  79
  80 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
  81 typedef unsigned int mpls_label_t;
  82
  83 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
  84  * to zero you have set that variable to explicit-null which was probably not
  85  * your intent. The work-around is to use one bit to indicate if the
  86  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
  87  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
  88  */
  89 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
  90
  91 /* LSP types. */
  92 enum lsp_types_t
  93 {
  94   ZEBRA_LSP_NONE = 0,        /* No LSP. */
  95   ZEBRA_LSP_STATIC = 1,      /* Static LSP. */
  96   ZEBRA_LSP_LDP = 2,         /* LDP LSP. */
  97   ZEBRA_LSP_BGP = 3          /* BGP LSP. */
  98 };
  99
 100 /* Functions for basic label operations. */
 101
 102 /* Encode a label stack entry from fields; convert to network byte-order as
 103  * the Netlink interface expects MPLS labels to be in this format.
 104  */
 105 static inline mpls_lse_t
 106 mpls_lse_encode (mpls_label_t label, u_int32_t ttl,
 107                  u_int32_t exp, u_int32_t bos)
 108 {
 109   mpls_lse_t lse;
 110   lse = htonl ((label << MPLS_LS_LABEL_SHIFT) |
 111                (exp << MPLS_LS_EXP_SHIFT) |
 112                (bos ? (1 << MPLS_LS_S_SHIFT) : 0) |
 113                (ttl << MPLS_LS_TTL_SHIFT));
 114   return lse;
 115 }
 116
 117 /* Extract the fields from a label stack entry after converting to host-byte
 118  * order. This is expected to be called only for messages received over the
 119  * Netlink interface.
 120  */
 121 static inline void
 122 mpls_lse_decode (mpls_lse_t lse, mpls_label_t *label,
 123                  u_int32_t *ttl, u_int32_t *exp, u_int32_t *bos)
 124 {
 125   mpls_lse_t local_lse;
 126
 127   local_lse = ntohl (lse);
 128   *label = MPLS_LABEL_VALUE(local_lse);
 129   *exp = MPLS_LABEL_EXP(local_lse);
 130   *bos = MPLS_LABEL_BOS(local_lse);
 131   *ttl = MPLS_LABEL_TTL(local_lse);
 132 }
 133
 134 /* Invalid label index value (when used with BGP Prefix-SID). Should
 135  * match the BGP definition.
 136  */
 137 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 138
 139
 140 /* Printable string for labels (with consideration for reserved values). */
 141 static inline char *
 142 label2str (mpls_label_t label, char *buf, size_t len)
 143 {
 144   switch(label) {
 145   case MPLS_V4_EXP_NULL_LABEL:
 146     strlcpy(buf, "IPv4 Explicit Null", len);
 147     return(buf);
 148   case MPLS_RA_LABEL:
 149     strlcpy(buf, "Router Alert", len);
 150     return(buf);
 151   case MPLS_V6_EXP_NULL_LABEL:
 152     strlcpy(buf, "IPv6 Explict Null", len);
 153     return(buf);
 154   case MPLS_IMP_NULL_LABEL:
 155     strlcpy(buf, "implicit-null", len);
 156     return(buf);
 157   case MPLS_ENTROPY_LABEL_INDICATOR:
 158     strlcpy(buf, "Entropy Label Indicator", len);
 159     return(buf);
 160   case MPLS_GAL_LABEL:
 161     strlcpy(buf, "Generic Associated Channel", len);
 162     return(buf);
 163   case MPLS_OAM_ALERT_LABEL:
 164     strlcpy(buf, "OAM Alert", len);
 165     return(buf);
 166   case MPLS_EXTENSION_LABEL:
 167     strlcpy(buf, "Extension", len);
 168     return(buf);
 169   default:
 170     if (label < 16)
 171       snprintf(buf, len, "Reserved (%u)", label);
 172     else
 173       snprintf(buf, len, "%u", label);
 174     return(buf);
 175   }
 176 }
 177
 178 /* constants used by ldpd */
 179 #define MPLS_LABEL_IPV4NULL     0               /* IPv4 Explicit NULL Label */
 180 #define MPLS_LABEL_RTALERT      1               /* Router Alert Label       */
 181 #define MPLS_LABEL_IPV6NULL     2               /* IPv6 Explicit NULL Label */
 182 #define MPLS_LABEL_IMPLNULL     3               /* Implicit NULL Label      */
 183 /*      MPLS_LABEL_RESERVED     4-15 */         /* Values 4-15 are reserved */
 184 #define MPLS_LABEL_RESERVED_MAX 15
 185 #define MPLS_LABEL_MAX          ((1 << 20) - 1)
 186
 187 #endif