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 <vxlan.h>
  27 #include <arpa/inet.h>
  28
  29 #ifdef __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 #ifdef MPLS_LABEL_MAX
  34 #undef MPLS_LABEL_MAX
  35 #endif
  36
  37 #define MPLS_LABEL_HELPSTR                                                     \
  38         "Specify label(s) for this route\nOne or more "                        \
  39         "labels in the range (16-1048575) separated by '/'\n"
  40
  41 /* Well-known MPLS label values (RFC 3032 etc). */
  42 #define MPLS_LABEL_IPV4_EXPLICIT_NULL  0       /* [RFC3032] */
  43 #define MPLS_LABEL_ROUTER_ALERT        1       /* [RFC3032] */
  44 #define MPLS_LABEL_IPV6_EXPLICIT_NULL  2       /* [RFC3032] */
  45 #define MPLS_LABEL_IMPLICIT_NULL       3       /* [RFC3032] */
  46 #define MPLS_LABEL_ELI                 7       /* [RFC6790] */
  47 #define MPLS_LABEL_GAL                 13      /* [RFC5586] */
  48 #define MPLS_LABEL_OAM_ALERT           14      /* [RFC3429] */
  49 #define MPLS_LABEL_EXTENSION           15      /* [RFC7274] */
  50 #define MPLS_LABEL_MAX                 1048575
  51 #define MPLS_LABEL_VALUE_MASK          0x000FFFFF
  52 #define MPLS_LABEL_NONE                0xFFFFFFFF /* for internal use only */
  53
  54 /* Minimum and maximum label values */
  55 #define MPLS_LABEL_RESERVED_MIN            0
  56 #define MPLS_LABEL_RESERVED_MAX            15
  57 #define MPLS_LABEL_UNRESERVED_MIN          16
  58 #define MPLS_LABEL_UNRESERVED_MAX          1048575
  59 #define MPLS_LABEL_BASE_ANY                0
  60
  61 /* Default min and max SRGB label range */
  62 /* Even if the SRGB allows to manage different Label space between routers,
  63  * if an operator want to use the same SRGB for all its router, we must fix
  64  * a common range. However, Cisco start its SRGB at 16000 and Juniper ends
  65  * its SRGB at 16384 for OSPF. Thus, by fixing the minimum SRGB label to
  66  * 8000 we could deal with both Cisco and Juniper.
  67  */
  68 #define MPLS_DEFAULT_MIN_SRGB_LABEL        8000
  69 #define MPLS_DEFAULT_MAX_SRGB_LABEL        50000
  70 #define MPLS_DEFAULT_MIN_SRGB_SIZE         5000
  71 #define MPLS_DEFAULT_MAX_SRGB_SIZE         20000
  72
  73 /* Maximum # labels that can be pushed. */
  74 #define MPLS_MAX_LABELS                    16
  75
  76 #define IS_MPLS_RESERVED_LABEL(label) (label <= MPLS_LABEL_RESERVED_MAX)
  77
  78 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  79         (label >= MPLS_LABEL_UNRESERVED_MIN                                    \
  80          && label <= MPLS_LABEL_UNRESERVED_MAX)
  81
  82 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  83  * label, EXP, BOS and TTL fields.
  84  */
  85 typedef unsigned int mpls_lse_t;
  86
  87 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  88 #define MPLS_LS_LABEL_SHIFT            12
  89 #define MPLS_LS_EXP_MASK               0x00000E00
  90 #define MPLS_LS_EXP_SHIFT              9
  91 #define MPLS_LS_S_MASK                 0x00000100
  92 #define MPLS_LS_S_SHIFT                8
  93 #define MPLS_LS_TTL_MASK               0x000000FF
  94 #define MPLS_LS_TTL_SHIFT              0
  95
  96 #define MPLS_LABEL_VALUE(lse)                                                  \
  97         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  98 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  99 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
 100 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
 101
 102 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
 103
 104 #define MPLS_LABEL_LEN_BITS            20
 105
 106 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
 107 typedef unsigned int mpls_label_t;
 108
 109 struct mpls_label_stack {
 110         uint8_t num_labels;
 111         uint8_t reserved[3];
 112         mpls_label_t label[0]; /* 1 or more labels */
 113 };
 114
 115 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
 116  * to zero you have set that variable to explicit-null which was probably not
 117  * your intent. The work-around is to use one bit to indicate if the
 118  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
 119  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
 120  */
 121 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
 122
 123 /* LSP types. */
 124 enum lsp_types_t {
 125         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 126         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 127         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 128         ZEBRA_LSP_BGP = 3,    /* BGP LSP. */
 129         ZEBRA_LSP_OSPF_SR = 4,/* OSPF Segment Routing LSP. */
 130         ZEBRA_LSP_ISIS_SR = 5,/* IS-IS Segment Routing LSP. */
 131         ZEBRA_LSP_SHARP = 6,  /* Identifier for test protocol */
 132         ZEBRA_LSP_SRTE = 7,   /* SR-TE LSP */
 133         ZEBRA_LSP_EVPN = 8,  /* EVPN VNI Label */
 134 };
 135
 136 /* Functions for basic label operations. */
 137
 138 static inline void vni2label(vni_t vni, mpls_label_t *label)
 139 {
 140         uint8_t *tag = (uint8_t *)label;
 141
 142         assert(tag);
 143
 144         tag[0] = (vni >> 16) & 0xFF;
 145         tag[1] = (vni >> 8) & 0xFF;
 146         tag[2] = vni & 0xFF;
 147 }
 148
 149 static inline vni_t label2vni(const mpls_label_t *label)
 150 {
 151         uint8_t *tag = (uint8_t *)label;
 152         vni_t vni;
 153
 154         assert(tag);
 155
 156         vni = ((uint32_t)*tag++ << 16);
 157         vni |= (uint32_t)*tag++ << 8;
 158         vni |= (uint32_t)(*tag & 0xFF);
 159
 160         return vni;
 161 }
 162
 163 /* Encode a label stack entry from fields; convert to network byte-order as
 164  * the Netlink interface expects MPLS labels to be in this format.
 165  */
 166 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, uint32_t ttl,
 167                                          uint32_t exp, uint32_t bos)
 168 {
 169         mpls_lse_t lse;
 170         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 171                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 172                     | (ttl << MPLS_LS_TTL_SHIFT));
 173         return lse;
 174 }
 175
 176 /* Extract the fields from a label stack entry after converting to host-byte
 177  * order. This is expected to be called only for messages received over the
 178  * Netlink interface.
 179  */
 180 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 181                                    uint32_t *ttl, uint32_t *exp, uint32_t *bos)
 182 {
 183         mpls_lse_t local_lse;
 184
 185         local_lse = ntohl(lse);
 186         *label = MPLS_LABEL_VALUE(local_lse);
 187         *exp = MPLS_LABEL_EXP(local_lse);
 188         *bos = MPLS_LABEL_BOS(local_lse);
 189         *ttl = MPLS_LABEL_TTL(local_lse);
 190 }
 191
 192 /* Invalid label index value (when used with BGP Prefix-SID). Should
 193  * match the BGP definition.
 194  */
 195 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 196
 197 /* Printable string for labels (with consideration for reserved values). */
 198 static inline char *label2str(mpls_label_t label, enum lsp_types_t type,
 199                               char *buf, size_t len)
 200 {
 201         if (type == ZEBRA_LSP_EVPN) {
 202                 snprintf(buf, len, "%u", label2vni(&label));
 203                 return (buf);
 204         }
 205
 206         switch (label) {
 207         case MPLS_LABEL_IPV4_EXPLICIT_NULL:
 208                 strlcpy(buf, "IPv4 Explicit Null", len);
 209                 return (buf);
 210         case MPLS_LABEL_ROUTER_ALERT:
 211                 strlcpy(buf, "Router Alert", len);
 212                 return (buf);
 213         case MPLS_LABEL_IPV6_EXPLICIT_NULL:
 214                 strlcpy(buf, "IPv6 Explicit Null", len);
 215                 return (buf);
 216         case MPLS_LABEL_IMPLICIT_NULL:
 217                 strlcpy(buf, "implicit-null", len);
 218                 return (buf);
 219         case MPLS_LABEL_ELI:
 220                 strlcpy(buf, "Entropy Label Indicator", len);
 221                 return (buf);
 222         case MPLS_LABEL_GAL:
 223                 strlcpy(buf, "Generic Associated Channel", len);
 224                 return (buf);
 225         case MPLS_LABEL_OAM_ALERT:
 226                 strlcpy(buf, "OAM Alert", len);
 227                 return (buf);
 228         case MPLS_LABEL_EXTENSION:
 229                 strlcpy(buf, "Extension", len);
 230                 return (buf);
 231         default:
 232                 if (label < 16)
 233                         snprintf(buf, len, "Reserved (%u)", label);
 234                 else
 235                         snprintf(buf, len, "%u", label);
 236                 return buf;
 237         }
 238 }
 239
 240 /*
 241  * String to label conversion, labels separated by '/'.
 242  */
 243 int mpls_str2label(const char *label_str, uint8_t *num_labels,
 244                    mpls_label_t *labels);
 245
 246 /* Generic string buffer for label-stack-to-str */
 247 #define MPLS_LABEL_STRLEN 1024
 248
 249 /*
 250  * Label to string conversion, labels in string separated by '/'.
 251  */
 252 char *mpls_label2str(uint8_t num_labels, const mpls_label_t *labels, char *buf,
 253                      int len, enum lsp_types_t type, int pretty);
 254
 255 #ifdef __cplusplus
 256 }
 257 #endif
 258
 259 #endif