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 <zebra.h>
  26 #include <arpa/inet.h>
  27
  28 #ifdef MPLS_LABEL_MAX
  29 #undef MPLS_LABEL_MAX
  30 #endif
  31
  32 #define MPLS_LABEL_HELPSTR                                                     \
  33         "Specify label(s) for this route\nOne or more "                        \
  34         "labels in the range (16-1048575) separated by '/'\n"
  35
  36 /* Well-known MPLS label values (RFC 3032 etc). */
  37 #define MPLS_LABEL_IPV4_EXPLICIT_NULL  0       /* [RFC3032] */
  38 #define MPLS_LABEL_ROUTER_ALERT        1       /* [RFC3032] */
  39 #define MPLS_LABEL_IPV6_EXPLICIT_NULL  2       /* [RFC3032] */
  40 #define MPLS_LABEL_IMPLICIT_NULL       3       /* [RFC3032] */
  41 #define MPLS_LABEL_ELI                 7       /* [RFC6790] */
  42 #define MPLS_LABEL_GAL                 13      /* [RFC5586] */
  43 #define MPLS_LABEL_OAM_ALERT           14      /* [RFC3429] */
  44 #define MPLS_LABEL_EXTENSION           15      /* [RFC7274] */
  45 #define MPLS_LABEL_MAX                 1048575
  46 #define MPLS_LABEL_NONE                0xFFFFFFFF /* for internal use only */
  47
  48 /* Minimum and maximum label values */
  49 #define MPLS_LABEL_RESERVED_MIN            0
  50 #define MPLS_LABEL_RESERVED_MAX            15
  51 #define MPLS_LABEL_UNRESERVED_MIN          16
  52 #define MPLS_LABEL_UNRESERVED_MAX          1048575
  53
  54 /* Default min and max SRGB label range */
  55 /* Even if the SRGB allows to manage different Label space between routers,
  56  * if an operator want to use the same SRGB for all its router, we must fix
  57  * a common range. However, Cisco start its SRGB at 16000 and Juniper ends
  58  * its SRGB at 16384 for OSPF. Thus, by fixing the minimum SRGB label to
  59  * 8000 we could deal with both Cisco and Juniper.
  60  */
  61 #define MPLS_DEFAULT_MIN_SRGB_LABEL        8000
  62 #define MPLS_DEFAULT_MAX_SRGB_LABEL        50000
  63 #define MPLS_DEFAULT_MIN_SRGB_SIZE         5000
  64 #define MPLS_DEFAULT_MAX_SRGB_SIZE         20000
  65
  66 /* Maximum # labels that can be pushed. */
  67 #define MPLS_MAX_LABELS                    16
  68
  69 #define IS_MPLS_RESERVED_LABEL(label)                                          \
  70         (label >= MPLS_LABEL_RESERVED_MIN && label <= MPLS_LABEL_RESERVED_MAX)
  71
  72 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  73         (label >= MPLS_LABEL_UNRESERVED_MIN                                    \
  74          && label <= MPLS_LABEL_UNRESERVED_MAX)
  75
  76 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  77  * label, EXP, BOS and TTL fields.
  78  */
  79 typedef unsigned int mpls_lse_t;
  80
  81 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  82 #define MPLS_LS_LABEL_SHIFT            12
  83 #define MPLS_LS_EXP_MASK               0x00000E00
  84 #define MPLS_LS_EXP_SHIFT              9
  85 #define MPLS_LS_S_MASK                 0x00000100
  86 #define MPLS_LS_S_SHIFT                8
  87 #define MPLS_LS_TTL_MASK               0x000000FF
  88 #define MPLS_LS_TTL_SHIFT              0
  89
  90 #define MPLS_LABEL_VALUE(lse)                                                  \
  91         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  92 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  93 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  94 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  95
  96 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  97
  98 #define MPLS_LABEL_LEN_BITS            20
  99
 100 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
 101 typedef unsigned int mpls_label_t;
 102
 103 struct mpls_label_stack {
 104         uint8_t num_labels;
 105         uint8_t reserved[3];
 106         mpls_label_t label[0]; /* 1 or more labels */
 107 };
 108
 109 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
 110  * to zero you have set that variable to explicit-null which was probably not
 111  * your intent. The work-around is to use one bit to indicate if the
 112  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
 113  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
 114  */
 115 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
 116
 117 /* LSP types. */
 118 enum lsp_types_t {
 119         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 120         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 121         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 122         ZEBRA_LSP_BGP = 3,    /* BGP LSP. */
 123         ZEBRA_LSP_SR = 4,     /* Segment Routing LSP. */
 124         ZEBRA_LSP_SHARP = 5,  /* Identifier for test protocol */
 125 };
 126
 127 /* Functions for basic label operations. */
 128
 129 /* Encode a label stack entry from fields; convert to network byte-order as
 130  * the Netlink interface expects MPLS labels to be in this format.
 131  */
 132 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, uint32_t ttl,
 133                                          uint32_t exp, uint32_t bos)
 134 {
 135         mpls_lse_t lse;
 136         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 137                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 138                     | (ttl << MPLS_LS_TTL_SHIFT));
 139         return lse;
 140 }
 141
 142 /* Extract the fields from a label stack entry after converting to host-byte
 143  * order. This is expected to be called only for messages received over the
 144  * Netlink interface.
 145  */
 146 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 147                                    uint32_t *ttl, uint32_t *exp, uint32_t *bos)
 148 {
 149         mpls_lse_t local_lse;
 150
 151         local_lse = ntohl(lse);
 152         *label = MPLS_LABEL_VALUE(local_lse);
 153         *exp = MPLS_LABEL_EXP(local_lse);
 154         *bos = MPLS_LABEL_BOS(local_lse);
 155         *ttl = MPLS_LABEL_TTL(local_lse);
 156 }
 157
 158 /* Invalid label index value (when used with BGP Prefix-SID). Should
 159  * match the BGP definition.
 160  */
 161 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 162
 163 /* Printable string for labels (with consideration for reserved values). */
 164 static inline char *label2str(mpls_label_t label, char *buf, size_t len)
 165 {
 166         switch (label) {
 167         case MPLS_LABEL_IPV4_EXPLICIT_NULL:
 168                 strlcpy(buf, "IPv4 Explicit Null", len);
 169                 return (buf);
 170         case MPLS_LABEL_ROUTER_ALERT:
 171                 strlcpy(buf, "Router Alert", len);
 172                 return (buf);
 173         case MPLS_LABEL_IPV6_EXPLICIT_NULL:
 174                 strlcpy(buf, "IPv6 Explicit Null", len);
 175                 return (buf);
 176         case MPLS_LABEL_IMPLICIT_NULL:
 177                 strlcpy(buf, "implicit-null", len);
 178                 return (buf);
 179         case MPLS_LABEL_ELI:
 180                 strlcpy(buf, "Entropy Label Indicator", len);
 181                 return (buf);
 182         case MPLS_LABEL_GAL:
 183                 strlcpy(buf, "Generic Associated Channel", len);
 184                 return (buf);
 185         case MPLS_LABEL_OAM_ALERT:
 186                 strlcpy(buf, "OAM Alert", len);
 187                 return (buf);
 188         case MPLS_LABEL_EXTENSION:
 189                 strlcpy(buf, "Extension", len);
 190                 return (buf);
 191         default:
 192                 if (label < 16)
 193                         snprintf(buf, len, "Reserved (%u)", label);
 194                 else
 195                         snprintf(buf, len, "%u", label);
 196                 return (buf);
 197         }
 198 }
 199
 200 /*
 201  * String to label conversion, labels separated by '/'.
 202  */
 203 int mpls_str2label(const char *label_str, uint8_t *num_labels,
 204                    mpls_label_t *labels);
 205
 206 /*
 207  * Label to string conversion, labels in string separated by '/'.
 208  */
 209 char *mpls_label2str(uint8_t num_labels, mpls_label_t *labels, char *buf,
 210                      int len, int pretty);
 211
 212 #endif