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 /* Even if the SRGB allows to manage different Label space between routers,
  45  * if an operator want to use the same SRGB for all its router, we must fix
  46  * a common range. However, Cisco start its SRGB at 16000 and Juniper ends
  47  * its SRGB at 16384 for OSPF. Thus, by fixing the minimum SRGB label to
  48  * 8000 we could deal with both Cisco and Juniper.
  49  */
  50 #define MPLS_DEFAULT_MIN_SRGB_LABEL        8000
  51 #define MPLS_DEFAULT_MAX_SRGB_LABEL        50000
  52 #define MPLS_DEFAULT_MIN_SRGB_SIZE         5000
  53 #define MPLS_DEFAULT_MAX_SRGB_SIZE         20000
  54
  55 /* Maximum # labels that can be pushed. */
  56 #define MPLS_MAX_LABELS                    16
  57
  58 #define IS_MPLS_RESERVED_LABEL(label)                                          \
  59         (label >= MPLS_MIN_RESERVED_LABEL && label <= MPLS_MAX_RESERVED_LABEL)
  60
  61 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  62         (label >= MPLS_MIN_UNRESERVED_LABEL                                    \
  63          && label <= MPLS_MAX_UNRESERVED_LABEL)
  64
  65 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  66  * label, EXP, BOS and TTL fields.
  67  */
  68 typedef unsigned int mpls_lse_t;
  69
  70 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  71 #define MPLS_LS_LABEL_SHIFT            12
  72 #define MPLS_LS_EXP_MASK               0x00000E00
  73 #define MPLS_LS_EXP_SHIFT              9
  74 #define MPLS_LS_S_MASK                 0x00000100
  75 #define MPLS_LS_S_SHIFT                8
  76 #define MPLS_LS_TTL_MASK               0x000000FF
  77 #define MPLS_LS_TTL_SHIFT              0
  78
  79 #define MPLS_LABEL_VALUE(lse)                                                  \
  80         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  81 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  82 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  83 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  84
  85 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  86
  87 #define MPLS_LABEL_LEN_BITS            20
  88
  89 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
  90 typedef unsigned int mpls_label_t;
  91
  92 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
  93  * to zero you have set that variable to explicit-null which was probably not
  94  * your intent. The work-around is to use one bit to indicate if the
  95  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
  96  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
  97  */
  98 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
  99
 100 /* LSP types. */
 101 enum lsp_types_t {
 102         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 103         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 104         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 105         ZEBRA_LSP_BGP = 3,    /* BGP LSP. */
 106         ZEBRA_LSP_SR = 4      /* Segment Routing LSP. */
 107 };
 108
 109 /* Functions for basic label operations. */
 110
 111 /* Encode a label stack entry from fields; convert to network byte-order as
 112  * the Netlink interface expects MPLS labels to be in this format.
 113  */
 114 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, u_int32_t ttl,
 115                                          u_int32_t exp, u_int32_t bos)
 116 {
 117         mpls_lse_t lse;
 118         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 119                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 120                     | (ttl << MPLS_LS_TTL_SHIFT));
 121         return lse;
 122 }
 123
 124 /* Extract the fields from a label stack entry after converting to host-byte
 125  * order. This is expected to be called only for messages received over the
 126  * Netlink interface.
 127  */
 128 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 129                                    u_int32_t *ttl, u_int32_t *exp,
 130                                    u_int32_t *bos)
 131 {
 132         mpls_lse_t local_lse;
 133
 134         local_lse = ntohl(lse);
 135         *label = MPLS_LABEL_VALUE(local_lse);
 136         *exp = MPLS_LABEL_EXP(local_lse);
 137         *bos = MPLS_LABEL_BOS(local_lse);
 138         *ttl = MPLS_LABEL_TTL(local_lse);
 139 }
 140
 141 /* Invalid label index value (when used with BGP Prefix-SID). Should
 142  * match the BGP definition.
 143  */
 144 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 145
 146 /* Printable string for labels (with consideration for reserved values). */
 147 static inline char *label2str(mpls_label_t label, char *buf, size_t len)
 148 {
 149         switch (label) {
 150         case MPLS_V4_EXP_NULL_LABEL:
 151                 strlcpy(buf, "IPv4 Explicit Null", len);
 152                 return (buf);
 153         case MPLS_RA_LABEL:
 154                 strlcpy(buf, "Router Alert", len);
 155                 return (buf);
 156         case MPLS_V6_EXP_NULL_LABEL:
 157                 strlcpy(buf, "IPv6 Explict Null", len);
 158                 return (buf);
 159         case MPLS_IMP_NULL_LABEL:
 160                 strlcpy(buf, "implicit-null", len);
 161                 return (buf);
 162         case MPLS_ENTROPY_LABEL_INDICATOR:
 163                 strlcpy(buf, "Entropy Label Indicator", len);
 164                 return (buf);
 165         case MPLS_GAL_LABEL:
 166                 strlcpy(buf, "Generic Associated Channel", len);
 167                 return (buf);
 168         case MPLS_OAM_ALERT_LABEL:
 169                 strlcpy(buf, "OAM Alert", len);
 170                 return (buf);
 171         case MPLS_EXTENSION_LABEL:
 172                 strlcpy(buf, "Extension", len);
 173                 return (buf);
 174         default:
 175                 if (label < 16)
 176                         snprintf(buf, len, "Reserved (%u)", label);
 177                 else
 178                         snprintf(buf, len, "%u", label);
 179                 return (buf);
 180         }
 181 }
 182
 183 /* constants used by ldpd */
 184 #define MPLS_LABEL_IPV4NULL     0               /* IPv4 Explicit NULL Label */
 185 #define MPLS_LABEL_RTALERT      1               /* Router Alert Label       */
 186 #define MPLS_LABEL_IPV6NULL     2               /* IPv6 Explicit NULL Label */
 187 #define MPLS_LABEL_IMPLNULL     3               /* Implicit NULL Label      */
 188         /*      MPLS_LABEL_RESERVED     4-15 */ /* Values 4-15 are reserved */
 189 #define MPLS_LABEL_RESERVED_MAX 15
 190 #define MPLS_LABEL_MAX          ((1 << 20) - 1)
 191
 192 #endif