lib/mpls.h

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * MPLS definitions
   4  * Copyright 2015 Cumulus Networks, Inc.
   5  */
   6
   7 #ifndef _QUAGGA_MPLS_H
   8 #define _QUAGGA_MPLS_H
   9
  10 #include <zebra.h>
  11 #include <vxlan.h>
  12 #include <arpa/inet.h>
  13
  14 #ifdef __cplusplus
  15 extern "C" {
  16 #endif
  17
  18 #ifdef MPLS_LABEL_MAX
  19 #undef MPLS_LABEL_MAX
  20 #endif
  21
  22 #define MPLS_LABEL_HELPSTR                                                     \
  23         "Specify label(s) for this route\nOne or more "                        \
  24         "labels in the range (16-1048575) separated by '/'\n"
  25
  26 /* Well-known MPLS label values (RFC 3032 etc). */
  27 #define MPLS_LABEL_IPV4_EXPLICIT_NULL  0       /* [RFC3032] */
  28 #define MPLS_LABEL_ROUTER_ALERT        1       /* [RFC3032] */
  29 #define MPLS_LABEL_IPV6_EXPLICIT_NULL  2       /* [RFC3032] */
  30 #define MPLS_LABEL_IMPLICIT_NULL       3       /* [RFC3032] */
  31 #define MPLS_LABEL_ELI                 7       /* [RFC6790] */
  32 #define MPLS_LABEL_GAL                 13      /* [RFC5586] */
  33 #define MPLS_LABEL_OAM_ALERT           14      /* [RFC3429] */
  34 #define MPLS_LABEL_EXTENSION           15      /* [RFC7274] */
  35 #define MPLS_LABEL_MAX                 1048575
  36 #define MPLS_LABEL_VALUE_MASK          0x000FFFFF
  37 #define MPLS_LABEL_NONE                0xFFFFFFFF /* for internal use only */
  38
  39 /* Minimum and maximum label values */
  40 #define MPLS_LABEL_RESERVED_MIN            0
  41 #define MPLS_LABEL_RESERVED_MAX            15
  42 #define MPLS_LABEL_UNRESERVED_MIN          16
  43 #define MPLS_LABEL_UNRESERVED_MAX          1048575
  44 #define MPLS_LABEL_BASE_ANY                0
  45
  46 /* Default min and max SRGB label range */
  47 /* Even if the SRGB allows to manage different Label space between routers,
  48  * if an operator want to use the same SRGB for all its router, we must fix
  49  * a common range. However, Cisco start its SRGB at 16000 and Juniper ends
  50  * its SRGB at 16384 for OSPF. Thus, by fixing the minimum SRGB label to
  51  * 8000 we could deal with both Cisco and Juniper.
  52  */
  53 #define MPLS_DEFAULT_MIN_SRGB_LABEL        8000
  54 #define MPLS_DEFAULT_MAX_SRGB_LABEL        50000
  55 #define MPLS_DEFAULT_MIN_SRGB_SIZE         5000
  56 #define MPLS_DEFAULT_MAX_SRGB_SIZE         20000
  57
  58 /* Maximum # labels that can be pushed. */
  59 #define MPLS_MAX_LABELS                    16
  60
  61 #define IS_MPLS_RESERVED_LABEL(label) (label <= MPLS_LABEL_RESERVED_MAX)
  62
  63 #define IS_MPLS_UNRESERVED_LABEL(label)                                        \
  64         (label >= MPLS_LABEL_UNRESERVED_MIN                                    \
  65          && label <= MPLS_LABEL_UNRESERVED_MAX)
  66
  67 /* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
  68  * label, EXP, BOS and TTL fields.
  69  */
  70 typedef unsigned int mpls_lse_t;
  71
  72 #define MPLS_LS_LABEL_MASK             0xFFFFF000
  73 #define MPLS_LS_LABEL_SHIFT            12
  74 #define MPLS_LS_EXP_MASK               0x00000E00
  75 #define MPLS_LS_EXP_SHIFT              9
  76 #define MPLS_LS_S_MASK                 0x00000100
  77 #define MPLS_LS_S_SHIFT                8
  78 #define MPLS_LS_TTL_MASK               0x000000FF
  79 #define MPLS_LS_TTL_SHIFT              0
  80
  81 #define MPLS_LABEL_VALUE(lse)                                                  \
  82         ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
  83 #define MPLS_LABEL_EXP(lse) ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
  84 #define MPLS_LABEL_BOS(lse) ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
  85 #define MPLS_LABEL_TTL(lse) ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
  86
  87 #define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
  88
  89 #define MPLS_LABEL_LEN_BITS            20
  90
  91 /* MPLS label value as a 32-bit (mostly we only care about the label value). */
  92 typedef unsigned int mpls_label_t;
  93
  94 struct mpls_label_stack {
  95         uint8_t num_labels;
  96         uint8_t reserved[3];
  97         mpls_label_t label[0]; /* 1 or more labels */
  98 };
  99
 100 /* The MPLS explicit-null label is 0 which means when you memset a mpls_label_t
 101  * to zero you have set that variable to explicit-null which was probably not
 102  * your intent. The work-around is to use one bit to indicate if the
 103  * mpls_label_t has been set by the user. MPLS_INVALID_LABEL has this bit clear
 104  * so that we can use MPLS_INVALID_LABEL to initialize mpls_label_t variables.
 105  */
 106 #define MPLS_INVALID_LABEL                 0xFFFDFFFF
 107
 108 /* LSP types. */
 109 enum lsp_types_t {
 110         ZEBRA_LSP_NONE = 0,   /* No LSP. */
 111         ZEBRA_LSP_STATIC = 1, /* Static LSP. */
 112         ZEBRA_LSP_LDP = 2,    /* LDP LSP. */
 113         ZEBRA_LSP_BGP = 3,    /* BGP LSP. */
 114         ZEBRA_LSP_OSPF_SR = 4,/* OSPF Segment Routing LSP. */
 115         ZEBRA_LSP_ISIS_SR = 5,/* IS-IS Segment Routing LSP. */
 116         ZEBRA_LSP_SHARP = 6,  /* Identifier for test protocol */
 117         ZEBRA_LSP_SRTE = 7,   /* SR-TE LSP */
 118         ZEBRA_LSP_EVPN = 8,  /* EVPN VNI Label */
 119 };
 120
 121 /* Functions for basic label operations. */
 122
 123 static inline void vni2label(vni_t vni, mpls_label_t *label)
 124 {
 125         uint8_t *tag = (uint8_t *)label;
 126
 127         assert(tag);
 128
 129         tag[0] = (vni >> 16) & 0xFF;
 130         tag[1] = (vni >> 8) & 0xFF;
 131         tag[2] = vni & 0xFF;
 132 }
 133
 134 static inline vni_t label2vni(const mpls_label_t *label)
 135 {
 136         uint8_t *tag = (uint8_t *)label;
 137         vni_t vni;
 138
 139         assert(tag);
 140
 141         vni = ((uint32_t)*tag++ << 16);
 142         vni |= (uint32_t)*tag++ << 8;
 143         vni |= (uint32_t)(*tag & 0xFF);
 144
 145         return vni;
 146 }
 147
 148 /* Encode a label stack entry from fields; convert to network byte-order as
 149  * the Netlink interface expects MPLS labels to be in this format.
 150  */
 151 static inline mpls_lse_t mpls_lse_encode(mpls_label_t label, uint32_t ttl,
 152                                          uint32_t exp, uint32_t bos)
 153 {
 154         mpls_lse_t lse;
 155         lse = htonl((label << MPLS_LS_LABEL_SHIFT) | (exp << MPLS_LS_EXP_SHIFT)
 156                     | (bos ? (1 << MPLS_LS_S_SHIFT) : 0)
 157                     | (ttl << MPLS_LS_TTL_SHIFT));
 158         return lse;
 159 }
 160
 161 /* Extract the fields from a label stack entry after converting to host-byte
 162  * order. This is expected to be called only for messages received over the
 163  * Netlink interface.
 164  */
 165 static inline void mpls_lse_decode(mpls_lse_t lse, mpls_label_t *label,
 166                                    uint32_t *ttl, uint32_t *exp, uint32_t *bos)
 167 {
 168         mpls_lse_t local_lse;
 169
 170         local_lse = ntohl(lse);
 171         *label = MPLS_LABEL_VALUE(local_lse);
 172         *exp = MPLS_LABEL_EXP(local_lse);
 173         *bos = MPLS_LABEL_BOS(local_lse);
 174         *ttl = MPLS_LABEL_TTL(local_lse);
 175 }
 176
 177 /* Invalid label index value (when used with BGP Prefix-SID). Should
 178  * match the BGP definition.
 179  */
 180 #define MPLS_INVALID_LABEL_INDEX   0xFFFFFFFF
 181
 182 /* Printable string for labels (with consideration for reserved values). */
 183 static inline char *label2str(mpls_label_t label, enum lsp_types_t type,
 184                               char *buf, size_t len)
 185 {
 186         if (type == ZEBRA_LSP_EVPN) {
 187                 snprintf(buf, len, "%u", label2vni(&label));
 188                 return (buf);
 189         }
 190
 191         switch (label) {
 192         case MPLS_LABEL_IPV4_EXPLICIT_NULL:
 193                 strlcpy(buf, "IPv4 Explicit Null", len);
 194                 return (buf);
 195         case MPLS_LABEL_ROUTER_ALERT:
 196                 strlcpy(buf, "Router Alert", len);
 197                 return (buf);
 198         case MPLS_LABEL_IPV6_EXPLICIT_NULL:
 199                 strlcpy(buf, "IPv6 Explicit Null", len);
 200                 return (buf);
 201         case MPLS_LABEL_IMPLICIT_NULL:
 202                 strlcpy(buf, "implicit-null", len);
 203                 return (buf);
 204         case MPLS_LABEL_ELI:
 205                 strlcpy(buf, "Entropy Label Indicator", len);
 206                 return (buf);
 207         case MPLS_LABEL_GAL:
 208                 strlcpy(buf, "Generic Associated Channel", len);
 209                 return (buf);
 210         case MPLS_LABEL_OAM_ALERT:
 211                 strlcpy(buf, "OAM Alert", len);
 212                 return (buf);
 213         case MPLS_LABEL_EXTENSION:
 214                 strlcpy(buf, "Extension", len);
 215                 return (buf);
 216         default:
 217                 if (label < 16)
 218                         snprintf(buf, len, "Reserved (%u)", label);
 219                 else
 220                         snprintf(buf, len, "%u", label);
 221                 return buf;
 222         }
 223 }
 224
 225 /*
 226  * String to label conversion, labels separated by '/'.
 227  */
 228 int mpls_str2label(const char *label_str, uint8_t *num_labels,
 229                    mpls_label_t *labels);
 230
 231 /* Generic string buffer for label-stack-to-str */
 232 #define MPLS_LABEL_STRLEN 1024
 233
 234 /*
 235  * Label to string conversion, labels in string separated by '/'.
 236  */
 237 char *mpls_label2str(uint8_t num_labels, const mpls_label_t *labels, char *buf,
 238                      int len, enum lsp_types_t type, int pretty);
 239
 240 #ifdef __cplusplus
 241 }
 242 #endif
 243
 244 #endif