zebra/zebra_mpls_netlink.c

   1 /* MPLS forwarding table updates using netlink over GNU/Linux system.
   2  * Copyright (C) 2016  Cumulus Networks, Inc.
   3  *
   4  * This file is part of Quagga.
   5  *
   6  * Quagga is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * Quagga is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22 #include "zebra/rt.h"
  23 #include "zebra/rt_netlink.h"
  24 #include "zebra/zebra_mpls.h"
  25
  26 /*
  27  * Install Label Forwarding entry into the kernel.
  28  */
  29 int
  30 kernel_add_lsp (zebra_lsp_t *lsp)
  31 {
  32   int ret;
  33
  34   if (!lsp || !lsp->best_nhlfe) // unexpected
  35     return -1;
  36
  37   UNSET_FLAG (lsp->flags, LSP_FLAG_CHANGED);
  38   ret = netlink_mpls_multipath (RTM_NEWROUTE, lsp);
  39   if (!ret)
  40     SET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  41   else
  42     clear_nhlfe_installed (lsp);
  43
  44   return ret;
  45 }
  46
  47 /*
  48  * Update Label Forwarding entry in the kernel. This means that the Label
  49  * forwarding entry is already installed and needs an update - either a new
  50  * path is to be added, an installed path has changed (e.g., outgoing label)
  51  * or an installed path (but not all paths) has to be removed.
  52  * TODO: Performs a DEL followed by ADD now, need to change to REPLACE. Note
  53  * that REPLACE was originally implemented for IPv4 nexthops but removed as
  54  * it was not functioning when moving from swap to PHP as that was signaled
  55  * through the metric field (before kernel-MPLS). This shouldn't be an issue
  56  * any longer, so REPLACE can be reintroduced.
  57  */
  58 int
  59 kernel_upd_lsp (zebra_lsp_t *lsp)
  60 {
  61   int ret;
  62
  63   if (!lsp || !lsp->best_nhlfe) // unexpected
  64     return -1;
  65
  66   UNSET_FLAG (lsp->flags, LSP_FLAG_CHANGED);
  67
  68   /* First issue a DEL and clear the installed flag. */
  69   netlink_mpls_multipath (RTM_DELROUTE, lsp);
  70   UNSET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  71
  72   /* Then issue an ADD. */
  73   ret = netlink_mpls_multipath (RTM_NEWROUTE, lsp);
  74   if (!ret)
  75     SET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  76   else
  77     clear_nhlfe_installed (lsp);
  78
  79   return ret;
  80 }
  81
  82 /*
  83  * Delete Label Forwarding entry from the kernel.
  84  */
  85 int
  86 kernel_del_lsp (zebra_lsp_t *lsp)
  87 {
  88   if (!lsp) // unexpected
  89     return -1;
  90
  91   if (CHECK_FLAG (lsp->flags, LSP_FLAG_INSTALLED))
  92     {
  93       netlink_mpls_multipath (RTM_DELROUTE, lsp);
  94       UNSET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  95     }
  96
  97   return 0;
  98 }
  99
 100 int
 101 mpls_kernel_init (void)
 102 {
 103   struct stat st;
 104
 105   /*
 106    * Check if the MPLS module is loaded in the kernel.
 107    */
 108   if (stat ("/proc/sys/net/mpls", &st) != 0)
 109     return -1;
 110
 111   return 0;
 112 };