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