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 /* Maximum # labels that can be pushed. */
  48 #define MPLS_MAX_LABELS                    16
  49
  50 #define IS_MPLS_RESERVED_LABEL(label)                                          \
  51         (label >= MPLS_MIN_RESERVED_LABEL && label <= MPLS_MAX_RESERVED_LABEL)
  52
  53 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  54         (label >= MPLS_MIN_UNRESERVED_LABEL                                    \
  55          && label <= MPLS_MAX_UNRESERVED_LABEL)
  56
  57 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  58  * label, EXP, BOS and TTL fields.
  59  */
  60 typedef unsigned int mpls_lse_t;
  61
  62 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  63 #define MPLS_LS_LABEL_SHIFT            12
  64 #define MPLS_LS_EXP_MASK               0x00000E00
  65 #define MPLS_LS_EXP_SHIFT              9
  66 #define MPLS_LS_S_MASK                 0x00000100
  67 #define MPLS_LS_S_SHIFT                8
  68 #define MPLS_LS_TTL_MASK               0x000000FF
  69 #define MPLS_LS_TTL_SHIFT              0
  70
  71 #define MPLS_LABEL_VALUE(lse)                                                  \
  72         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  73 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  74 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  75 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  76
  77 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  78
  79 #define MPLS_LABEL_LEN_BITS            20
  80
  81 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
  82 typedef unsigned int mpls_label_t;
  83
  84 struct mpls_label_stack {
  85         uint8_t num_labels;
  86         uint8_t reserved[3];
  87         mpls_label_t label[0]; /* 1 or more labels */
  88 };
  89
  90 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
  91  * to zero you have set that variable to explicit-null which was probably not
  92  * your intent. The work-around is to use one bit to indicate if the
  93  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
  94  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
  95  */
  96 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
  97
  98 /* LSP types. */
  99 enum lsp_types_t {
 100         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 101         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 102         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 103         ZEBRA_LSP_BGP = 3     /* BGP LSP. */
 104 };
 105
 106 /* Functions for basic label operations. */
 107
 108 /* Encode a label stack entry from fields; convert to network byte-order as
 109  * the Netlink interface expects MPLS labels to be in this format.
 110  */
 111 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, u_int32_t ttl,
 112                                          u_int32_t exp, u_int32_t bos)
 113 {
 114         mpls_lse_t lse;
 115         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 116                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 117                     | (ttl << MPLS_LS_TTL_SHIFT));
 118         return lse;
 119 }
 120
 121 /* Extract the fields from a label stack entry after converting to host-byte
 122  * order. This is expected to be called only for messages received over the
 123  * Netlink interface.
 124  */
 125 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 126                                    u_int32_t *ttl, u_int32_t *exp,
 127                                    u_int32_t *bos)
 128 {
 129         mpls_lse_t local_lse;
 130
 131         local_lse = ntohl(lse);
 132         *label = MPLS_LABEL_VALUE(local_lse);
 133         *exp = MPLS_LABEL_EXP(local_lse);
 134         *bos = MPLS_LABEL_BOS(local_lse);
 135         *ttl = MPLS_LABEL_TTL(local_lse);
 136 }
 137
 138 /* Invalid label index value (when used with BGP Prefix-SID). Should
 139  * match the BGP definition.
 140  */
 141 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 142
 143 /* Printable string for labels (with consideration for reserved values). */
 144 static inline char *label2str(mpls_label_t label, char *buf, size_t len)
 145 {
 146         switch (label) {
 147         case MPLS_V4_EXP_NULL_LABEL:
 148                 strlcpy(buf, "IPv4 Explicit Null", len);
 149                 return (buf);
 150         case MPLS_RA_LABEL:
 151                 strlcpy(buf, "Router Alert", len);
 152                 return (buf);
 153         case MPLS_V6_EXP_NULL_LABEL:
 154                 strlcpy(buf, "IPv6 Explict Null", len);
 155                 return (buf);
 156         case MPLS_IMP_NULL_LABEL:
 157                 strlcpy(buf, "implicit-null", len);
 158                 return (buf);
 159         case MPLS_ENTROPY_LABEL_INDICATOR:
 160                 strlcpy(buf, "Entropy Label Indicator", len);
 161                 return (buf);
 162         case MPLS_GAL_LABEL:
 163                 strlcpy(buf, "Generic Associated Channel", len);
 164                 return (buf);
 165         case MPLS_OAM_ALERT_LABEL:
 166                 strlcpy(buf, "OAM Alert", len);
 167                 return (buf);
 168         case MPLS_EXTENSION_LABEL:
 169                 strlcpy(buf, "Extension", len);
 170                 return (buf);
 171         default:
 172                 if (label < 16)
 173                         snprintf(buf, len, "Reserved (%u)", label);
 174                 else
 175                         snprintf(buf, len, "%u", label);
 176                 return (buf);
 177         }
 178 }
 179
 180 /* constants used by ldpd */
 181 #define MPLS_LABEL_IPV4NULL     0               /* IPv4 Explicit NULL Label */
 182 #define MPLS_LABEL_RTALERT      1               /* Router Alert Label       */
 183 #define MPLS_LABEL_IPV6NULL     2               /* IPv6 Explicit NULL Label */
 184 #define MPLS_LABEL_IMPLNULL     3               /* Implicit NULL Label      */
 185         /*      MPLS_LABEL_RESERVED     4-15 */ /* Values 4-15 are reserved */
 186 #define MPLS_LABEL_RESERVED_MAX 15
 187 #define MPLS_LABEL_MAX          ((1 << 20) - 1)
 188
 189 #endif