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 /* Well-known MPLS label values (RFC 3032 etc). */
  32 #define MPLS_LABEL_IPV4_EXPLICIT_NULL  0       /* [RFC3032] */
  33 #define MPLS_LABEL_ROUTER_ALERT        1       /* [RFC3032] */
  34 #define MPLS_LABEL_IPV6_EXPLICIT_NULL  2       /* [RFC3032] */
  35 #define MPLS_LABEL_IMPLICIT_NULL       3       /* [RFC3032] */
  36 #define MPLS_LABEL_ELI                 7       /* [RFC6790] */
  37 #define MPLS_LABEL_GAL                 13      /* [RFC5586] */
  38 #define MPLS_LABEL_OAM_ALERT           14      /* [RFC3429] */
  39 #define MPLS_LABEL_EXTENSION           15      /* [RFC7274] */
  40 #define MPLS_LABEL_MAX                 1048575
  41 #define MPLS_LABEL_NONE                0xFFFFFFFF /* for internal use only */
  42
  43 /* Minimum and maximum label values */
  44 #define MPLS_LABEL_RESERVED_MIN            0
  45 #define MPLS_LABEL_RESERVED_MAX            15
  46 #define MPLS_LABEL_UNRESERVED_MIN          16
  47 #define MPLS_LABEL_UNRESERVED_MAX          1048575
  48
  49 /* Default min and max SRGB label range */
  50 /* Even if the SRGB allows to manage different Label space between routers,
  51  * if an operator want to use the same SRGB for all its router, we must fix
  52  * a common range. However, Cisco start its SRGB at 16000 and Juniper ends
  53  * its SRGB at 16384 for OSPF. Thus, by fixing the minimum SRGB label to
  54  * 8000 we could deal with both Cisco and Juniper.
  55  */
  56 #define MPLS_DEFAULT_MIN_SRGB_LABEL        8000
  57 #define MPLS_DEFAULT_MAX_SRGB_LABEL        50000
  58 #define MPLS_DEFAULT_MIN_SRGB_SIZE         5000
  59 #define MPLS_DEFAULT_MAX_SRGB_SIZE         20000
  60
  61 /* Maximum # labels that can be pushed. */
  62 #define MPLS_MAX_LABELS                    16
  63
  64 #define IS_MPLS_RESERVED_LABEL(label)                                          \
  65         (label >= MPLS_LABEL_RESERVED_MIN && label <= MPLS_LABEL_RESERVED_MAX)
  66
  67 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  68         (label >= MPLS_LABEL_UNRESERVED_MIN                                    \
  69          && label <= MPLS_LABEL_UNRESERVED_MAX)
  70
  71 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  72  * label, EXP, BOS and TTL fields.
  73  */
  74 typedef unsigned int mpls_lse_t;
  75
  76 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  77 #define MPLS_LS_LABEL_SHIFT            12
  78 #define MPLS_LS_EXP_MASK               0x00000E00
  79 #define MPLS_LS_EXP_SHIFT              9
  80 #define MPLS_LS_S_MASK                 0x00000100
  81 #define MPLS_LS_S_SHIFT                8
  82 #define MPLS_LS_TTL_MASK               0x000000FF
  83 #define MPLS_LS_TTL_SHIFT              0
  84
  85 #define MPLS_LABEL_VALUE(lse)                                                  \
  86         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  87 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  88 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  89 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  90
  91 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  92
  93 #define MPLS_LABEL_LEN_BITS            20
  94
  95 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
  96 typedef unsigned int mpls_label_t;
  97
  98 struct mpls_label_stack {
  99         uint8_t num_labels;
 100         uint8_t reserved[3];
 101         mpls_label_t label[0]; /* 1 or more labels */
 102 };
 103
 104 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
 105  * to zero you have set that variable to explicit-null which was probably not
 106  * your intent. The work-around is to use one bit to indicate if the
 107  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
 108  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
 109  */
 110 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
 111
 112 /* LSP types. */
 113 enum lsp_types_t {
 114         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 115         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 116         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 117         ZEBRA_LSP_BGP = 3,    /* BGP LSP. */
 118         ZEBRA_LSP_SR = 4,     /* Segment Routing LSP. */
 119         ZEBRA_LSP_SHARP = 5,  /* Identifier for test protocol */
 120 };
 121
 122 /* Functions for basic label operations. */
 123
 124 /* Encode a label stack entry from fields; convert to network byte-order as
 125  * the Netlink interface expects MPLS labels to be in this format.
 126  */
 127 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, u_int32_t ttl,
 128                                          u_int32_t exp, u_int32_t bos)
 129 {
 130         mpls_lse_t lse;
 131         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 132                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 133                     | (ttl << MPLS_LS_TTL_SHIFT));
 134         return lse;
 135 }
 136
 137 /* Extract the fields from a label stack entry after converting to host-byte
 138  * order. This is expected to be called only for messages received over the
 139  * Netlink interface.
 140  */
 141 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 142                                    u_int32_t *ttl, u_int32_t *exp,
 143                                    u_int32_t *bos)
 144 {
 145         mpls_lse_t local_lse;
 146
 147         local_lse = ntohl(lse);
 148         *label = MPLS_LABEL_VALUE(local_lse);
 149         *exp = MPLS_LABEL_EXP(local_lse);
 150         *bos = MPLS_LABEL_BOS(local_lse);
 151         *ttl = MPLS_LABEL_TTL(local_lse);
 152 }
 153
 154 /* Invalid label index value (when used with BGP Prefix-SID). Should
 155  * match the BGP definition.
 156  */
 157 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 158
 159 /* Printable string for labels (with consideration for reserved values). */
 160 static inline char *label2str(mpls_label_t label, char *buf, size_t len)
 161 {
 162         switch (label) {
 163         case MPLS_LABEL_IPV4_EXPLICIT_NULL:
 164                 strlcpy(buf, "IPv4 Explicit Null", len);
 165                 return (buf);
 166         case MPLS_LABEL_ROUTER_ALERT:
 167                 strlcpy(buf, "Router Alert", len);
 168                 return (buf);
 169         case MPLS_LABEL_IPV6_EXPLICIT_NULL:
 170                 strlcpy(buf, "IPv6 Explict Null", len);
 171                 return (buf);
 172         case MPLS_LABEL_IMPLICIT_NULL:
 173                 strlcpy(buf, "implicit-null", len);
 174                 return (buf);
 175         case MPLS_LABEL_ELI:
 176                 strlcpy(buf, "Entropy Label Indicator", len);
 177                 return (buf);
 178         case MPLS_LABEL_GAL:
 179                 strlcpy(buf, "Generic Associated Channel", len);
 180                 return (buf);
 181         case MPLS_LABEL_OAM_ALERT:
 182                 strlcpy(buf, "OAM Alert", len);
 183                 return (buf);
 184         case MPLS_LABEL_EXTENSION:
 185                 strlcpy(buf, "Extension", len);
 186                 return (buf);
 187         default:
 188                 if (label < 16)
 189                         snprintf(buf, len, "Reserved (%u)", label);
 190                 else
 191                         snprintf(buf, len, "%u", label);
 192                 return (buf);
 193         }
 194 }
 195
 196
 197 #endif