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
  17  * along with Quagga; see the file COPYING.  If not, write to the Free
  18  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19  * 02111-1307, USA.
  20  */
  21
  22 #include <zebra.h>
  23 #include "zebra/rt.h"
  24 #include "zebra/rt_netlink.h"
  25 #include "zebra/zebra_mpls.h"
  26
  27 /*
  28  * Install Label Forwarding entry into the kernel.
  29  */
  30 int
  31 kernel_add_lsp (zebra_lsp_t *lsp)
  32 {
  33   int ret;
  34
  35   if (!lsp || !lsp->best_nhlfe) // unexpected
  36     return -1;
  37
  38   UNSET_FLAG (lsp->flags, LSP_FLAG_CHANGED);
  39   ret = netlink_mpls_multipath (RTM_NEWROUTE, lsp);
  40   if (!ret)
  41     SET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  42   else
  43     clear_nhlfe_installed (lsp);
  44
  45   return ret;
  46 }
  47
  48 /*
  49  * Update Label Forwarding entry in the kernel. This means that the Label
  50  * forwarding entry is already installed and needs an update - either a new
  51  * path is to be added, an installed path has changed (e.g., outgoing label)
  52  * or an installed path (but not all paths) has to be removed.
  53  * TODO: Performs a DEL followed by ADD now, need to change to REPLACE. Note
  54  * that REPLACE was originally implemented for IPv4 nexthops but removed as
  55  * it was not functioning when moving from swap to PHP as that was signaled
  56  * through the metric field (before kernel-MPLS). This shouldn't be an issue
  57  * any longer, so REPLACE can be reintroduced.
  58  */
  59 int
  60 kernel_upd_lsp (zebra_lsp_t *lsp)
  61 {
  62   int ret;
  63
  64   if (!lsp || !lsp->best_nhlfe) // unexpected
  65     return -1;
  66
  67   UNSET_FLAG (lsp->flags, LSP_FLAG_CHANGED);
  68
  69   /* First issue a DEL and clear the installed flag. */
  70   netlink_mpls_multipath (RTM_DELROUTE, lsp);
  71   UNSET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  72
  73   /* Then issue an ADD. */
  74   ret = netlink_mpls_multipath (RTM_NEWROUTE, lsp);
  75   if (!ret)
  76     SET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  77   else
  78     clear_nhlfe_installed (lsp);
  79
  80   return ret;
  81 }
  82
  83 /*
  84  * Delete Label Forwarding entry from the kernel.
  85  */
  86 int
  87 kernel_del_lsp (zebra_lsp_t *lsp)
  88 {
  89   if (!lsp) // unexpected
  90     return -1;
  91
  92   if (CHECK_FLAG (lsp->flags, LSP_FLAG_INSTALLED))
  93     {
  94       netlink_mpls_multipath (RTM_DELROUTE, lsp);
  95       UNSET_FLAG (lsp->flags, LSP_FLAG_INSTALLED);
  96     }
  97
  98   return 0;
  99 }
 100
 101 int
 102 mpls_kernel_init (void)
 103 {
 104   struct stat st;
 105
 106   /*
 107    * Check if the MPLS module is loaded in the kernel.
 108    */
 109   if (stat ("/proc/sys/net/mpls", &st) != 0)
 110     return -1;
 111
 112   return 0;
 113 };