Quagga: Basic definitions for MPLS

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Reviewed-by:   Donald Sharp <sharpd@cumulusnetworks.com>

Ticket: CM-4804, ...
Reviewed By: CCR-3083
Testing Done: Not relevant

1 files changed, 172 insertions, 0 deletions

diff --git a/lib/mpls.h b/lib/mpls.h
new file mode 100644
index 000000000..888986897
--- /dev/null
+++ b/lib/mpls.h
@@ -0,0 +1,172 @@
+/*
+ * MPLS definitions
+ * Copyright 2015 Cumulus Networks, Inc.
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2, or (at your
+ * option) any later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _QUAGGA_MPLS_H
+#define _QUAGGA_MPLS_H
+
+/* Well-known MPLS label values (RFC 3032 etc). */
+#define MPLS_V4_EXP_NULL_LABEL             0
+#define MPLS_RA_LABEL                      1
+#define MPLS_V6_EXP_NULL_LABEL             2
+#define MPLS_IMP_NULL_LABEL                3
+#define MPLS_ENTROPY_LABEL_INDICATOR       7
+#define MPLS_GAL_LABEL                     13
+#define MPLS_OAM_ALERT_LABEL               14
+#define MPLS_EXTENSION_LABEL               15
+
+/* Minimum and maximum label values */
+#define MPLS_MIN_RESERVED_LABEL            0
+#define MPLS_MAX_RESERVED_LABEL            15
+#define MPLS_MIN_UNRESERVED_LABEL          16
+#define MPLS_MAX_UNRESERVED_LABEL          1048575
+
+#define IS_MPLS_RESERVED_LABEL(label) \
+        (label >= MPLS_MIN_RESERVED_LABEL && label <= MPLS_MAX_RESERVED_LABEL)
+
+#define IS_MPLS_UNRESERVED_LABEL(label) \
+        (label >= MPLS_MIN_UNRESERVED_LABEL && label <= MPLS_MAX_UNRESERVED_LABEL)
+
+/* Definitions for a MPLS label stack entry (RFC 3032). This encodes the
+ * label, EXP, BOS and TTL fields.
+ */
+typedef unsigned int mpls_lse_t;
+
+#define MPLS_LS_LABEL_MASK             0xFFFFF000
+#define MPLS_LS_LABEL_SHIFT            12
+#define MPLS_LS_EXP_MASK               0x00000E00
+#define MPLS_LS_EXP_SHIFT              9
+#define MPLS_LS_S_MASK                 0x00000100
+#define MPLS_LS_S_SHIFT                8
+#define MPLS_LS_TTL_MASK               0x000000FF
+#define MPLS_LS_TTL_SHIFT              0
+
+#define MPLS_LABEL_VALUE(lse) \
+        ((lse & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT)
+#define MPLS_LABEL_EXP(lse) \
+        ((lse & MPLS_LS_EXP_MASK) >> MPLS_LS_EXP_SHIFT)
+#define MPLS_LABEL_BOS(lse) \
+        ((lse & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT)
+#define MPLS_LABEL_TTL(lse) \
+        ((lse & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT)
+
+#define IS_MPLS_LABEL_BOS(ls)          (MPLS_LABEL_BOS(ls) == 1)
+
+#define MPLS_LABEL_LEN_BITS            20
+
+/* MPLS label value as a 32-bit (mostly we only care about the label value). */
+typedef unsigned int mpls_label_t;
+
+#define MPLS_INVALID_LABEL                 0xFFFFFFFF
+
+/* Functions for basic label operations. */
+
+/* Encode a label stack entry from fields; convert to network byte-order as
+ * the Netlink interface expects MPLS labels to be in this format.
+ */
+static inline mpls_lse_t
+mpls_lse_encode (mpls_label_t label, u_int32_t ttl,
+                 u_int32_t exp, u_int32_t bos)
+{
+  mpls_lse_t lse;
+  lse = htonl ((label << MPLS_LS_LABEL_SHIFT) |
+               (exp << MPLS_LS_EXP_SHIFT) |
+               (bos ? (1 << MPLS_LS_S_SHIFT) : 0) |
+               (ttl << MPLS_LS_TTL_SHIFT));
+  return lse;
+}
+
+/* Extract the fields from a label stack entry after converting to host-byte
+ * order. This is expected to be called only for messages received over the
+ * Netlink interface.
+ */
+static inline void
+mpls_lse_decode (mpls_lse_t lse, mpls_label_t *label,
+                 u_int32_t *ttl, u_int32_t *exp, u_int32_t *bos)
+{
+  mpls_lse_t local_lse;
+
+  local_lse = ntohl (lse);
+  *label = MPLS_LABEL_VALUE(local_lse);
+  *exp = MPLS_LABEL_EXP(local_lse);
+  *bos = MPLS_LABEL_BOS(local_lse);
+  *ttl = MPLS_LABEL_TTL(local_lse);
+}
+
+
+/* Printable string for labels (with consideration for reserved values). */
+static inline char *
+label2str (mpls_label_t label, char *buf, int len)
+{
+  switch(label) {
+  case MPLS_V4_EXP_NULL_LABEL:
+    strncpy(buf, "IPv4 Explicit Null", len);
+    return(buf);
+    break;
+  case MPLS_RA_LABEL:
+    strncpy(buf, "Router Alert", len);
+    return(buf);
+    break;
+  case MPLS_V6_EXP_NULL_LABEL:
+    strncpy(buf, "IPv6 Explict Null", len);
+    return(buf);
+    break;
+  case MPLS_IMP_NULL_LABEL:
+    strncpy(buf, "implicit-null", len);
+    return(buf);
+    break;
+  case MPLS_ENTROPY_LABEL_INDICATOR:
+    strncpy(buf, "Entropy Label Indicator", len);
+    return(buf);
+    break;
+  case MPLS_GAL_LABEL:
+    strncpy(buf, "Generic Associated Channel", len);
+    return(buf);
+    break;
+  case MPLS_OAM_ALERT_LABEL:
+    strncpy(buf, "OAM Alert", len);
+    return(buf);
+    break;
+  case MPLS_EXTENSION_LABEL:
+    strncpy(buf, "Extension", len);
+    return(buf);
+    break;
+  case 4:
+  case 5:
+  case 6:
+  case 8:
+  case 9:
+  case 10:
+  case 11:
+  case 12:
+    strncpy(buf, "Reserved", len);
+    return(buf);
+    break;
+  default:
+    sprintf(buf, "%u", label);
+    return(buf);
+  }
+
+  strncpy(buf, "Error", len);
+  return(buf);
+}
+
+#endif