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 #ifdef MPLS_LABEL_MAX
  28 #undef MPLS_LABEL_MAX
  29 #endif
  30
  31 #define MPLS_LABEL_HELPSTR                                                     \
  32         "Specify label(s) for this route\nOne or more "                        \
  33         "labels in the range (16-1048575) separated by '/'\n"
  34
  35 /* Well-known MPLS label values (RFC 3032 etc). */
  36 #define MPLS_LABEL_IPV4_EXPLICIT_NULL  0       /* [RFC3032] */
  37 #define MPLS_LABEL_ROUTER_ALERT        1       /* [RFC3032] */
  38 #define MPLS_LABEL_IPV6_EXPLICIT_NULL  2       /* [RFC3032] */
  39 #define MPLS_LABEL_IMPLICIT_NULL       3       /* [RFC3032] */
  40 #define MPLS_LABEL_ELI                 7       /* [RFC6790] */
  41 #define MPLS_LABEL_GAL                 13      /* [RFC5586] */
  42 #define MPLS_LABEL_OAM_ALERT           14      /* [RFC3429] */
  43 #define MPLS_LABEL_EXTENSION           15      /* [RFC7274] */
  44 #define MPLS_LABEL_MAX                 1048575
  45 #define MPLS_LABEL_NONE                0xFFFFFFFF /* for internal use only */
  46
  47 /* Minimum and maximum label values */
  48 #define MPLS_LABEL_RESERVED_MIN            0
  49 #define MPLS_LABEL_RESERVED_MAX            15
  50 #define MPLS_LABEL_UNRESERVED_MIN          16
  51 #define MPLS_LABEL_UNRESERVED_MAX          1048575
  52
  53 /* Default min and max SRGB label range */
  54 /* Even if the SRGB allows to manage different Label space between routers,
  55  * if an operator want to use the same SRGB for all its router, we must fix
  56  * a common range. However, Cisco start its SRGB at 16000 and Juniper ends
  57  * its SRGB at 16384 for OSPF. Thus, by fixing the minimum SRGB label to
  58  * 8000 we could deal with both Cisco and Juniper.
  59  */
  60 #define MPLS_DEFAULT_MIN_SRGB_LABEL        8000
  61 #define MPLS_DEFAULT_MAX_SRGB_LABEL        50000
  62 #define MPLS_DEFAULT_MIN_SRGB_SIZE         5000
  63 #define MPLS_DEFAULT_MAX_SRGB_SIZE         20000
  64
  65 /* Maximum # labels that can be pushed. */
  66 #define MPLS_MAX_LABELS                    16
  67
  68 #define IS_MPLS_RESERVED_LABEL(label)                                          \
  69         (label >= MPLS_LABEL_RESERVED_MIN && label <= MPLS_LABEL_RESERVED_MAX)
  70
  71 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  72         (label >= MPLS_LABEL_UNRESERVED_MIN                                    \
  73          && label <= MPLS_LABEL_UNRESERVED_MAX)
  74
  75 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  76  * label, EXP, BOS and TTL fields.
  77  */
  78 typedef unsigned int mpls_lse_t;
  79
  80 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  81 #define MPLS_LS_LABEL_SHIFT            12
  82 #define MPLS_LS_EXP_MASK               0x00000E00
  83 #define MPLS_LS_EXP_SHIFT              9
  84 #define MPLS_LS_S_MASK                 0x00000100
  85 #define MPLS_LS_S_SHIFT                8
  86 #define MPLS_LS_TTL_MASK               0x000000FF
  87 #define MPLS_LS_TTL_SHIFT              0
  88
  89 #define MPLS_LABEL_VALUE(lse)                                                  \
  90         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  91 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  92 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  93 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  94
  95 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  96
  97 #define MPLS_LABEL_LEN_BITS            20
  98
  99 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
 100 typedef unsigned int mpls_label_t;
 101
 102 struct mpls_label_stack {
 103         uint8_t num_labels;
 104         uint8_t reserved[3];
 105         mpls_label_t label[0]; /* 1 or more labels */
 106 };
 107
 108 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
 109  * to zero you have set that variable to explicit-null which was probably not
 110  * your intent. The work-around is to use one bit to indicate if the
 111  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
 112  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
 113  */
 114 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
 115
 116 /* LSP types. */
 117 enum lsp_types_t {
 118         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 119         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 120         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 121         ZEBRA_LSP_BGP = 3,    /* BGP LSP. */
 122         ZEBRA_LSP_SR = 4,     /* Segment Routing LSP. */
 123         ZEBRA_LSP_SHARP = 5,  /* Identifier for test protocol */
 124 };
 125
 126 /* Functions for basic label operations. */
 127
 128 /* Encode a label stack entry from fields; convert to network byte-order as
 129  * the Netlink interface expects MPLS labels to be in this format.
 130  */
 131 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, uint32_t ttl,
 132                                          uint32_t exp, uint32_t bos)
 133 {
 134         mpls_lse_t lse;
 135         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 136                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 137                     | (ttl << MPLS_LS_TTL_SHIFT));
 138         return lse;
 139 }
 140
 141 /* Extract the fields from a label stack entry after converting to host-byte
 142  * order. This is expected to be called only for messages received over the
 143  * Netlink interface.
 144  */
 145 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 146                                    uint32_t *ttl, uint32_t *exp, uint32_t *bos)
 147 {
 148         mpls_lse_t local_lse;
 149
 150         local_lse = ntohl(lse);
 151         *label = MPLS_LABEL_VALUE(local_lse);
 152         *exp = MPLS_LABEL_EXP(local_lse);
 153         *bos = MPLS_LABEL_BOS(local_lse);
 154         *ttl = MPLS_LABEL_TTL(local_lse);
 155 }
 156
 157 /* Invalid label index value (when used with BGP Prefix-SID). Should
 158  * match the BGP definition.
 159  */
 160 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 161
 162 /* Printable string for labels (with consideration for reserved values). */
 163 static inline char *label2str(mpls_label_t label, char *buf, size_t len)
 164 {
 165         switch (label) {
 166         case MPLS_LABEL_IPV4_EXPLICIT_NULL:
 167                 strlcpy(buf, "IPv4 Explicit Null", len);
 168                 return (buf);
 169         case MPLS_LABEL_ROUTER_ALERT:
 170                 strlcpy(buf, "Router Alert", len);
 171                 return (buf);
 172         case MPLS_LABEL_IPV6_EXPLICIT_NULL:
 173                 strlcpy(buf, "IPv6 Explict Null", len);
 174                 return (buf);
 175         case MPLS_LABEL_IMPLICIT_NULL:
 176                 strlcpy(buf, "implicit-null", len);
 177                 return (buf);
 178         case MPLS_LABEL_ELI:
 179                 strlcpy(buf, "Entropy Label Indicator", len);
 180                 return (buf);
 181         case MPLS_LABEL_GAL:
 182                 strlcpy(buf, "Generic Associated Channel", len);
 183                 return (buf);
 184         case MPLS_LABEL_OAM_ALERT:
 185                 strlcpy(buf, "OAM Alert", len);
 186                 return (buf);
 187         case MPLS_LABEL_EXTENSION:
 188                 strlcpy(buf, "Extension", len);
 189                 return (buf);
 190         default:
 191                 if (label < 16)
 192                         snprintf(buf, len, "Reserved (%u)", label);
 193                 else
 194                         snprintf(buf, len, "%u", label);
 195                 return (buf);
 196         }
 197 }
 198
 199
 200 #endif