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 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 kernel_upd_lsp(zebra_lsp_t *lsp)
  59 {
  60         int ret;
  61
  62         if (!lsp || !lsp->best_nhlfe) // unexpected
  63                 return -1;
  64
  65         UNSET_FLAG(lsp->flags, LSP_FLAG_CHANGED);
  66
  67         /* First issue a DEL and clear the installed flag. */
  68         netlink_mpls_multipath(RTM_DELROUTE, lsp);
  69         UNSET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
  70
  71         /* Then issue an ADD. */
  72         ret = netlink_mpls_multipath(RTM_NEWROUTE, lsp);
  73         if (!ret)
  74                 SET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
  75         else
  76                 clear_nhlfe_installed(lsp);
  77
  78         return ret;
  79 }
  80
  81 /*
  82  * Delete Label Forwarding entry from the kernel.
  83  */
  84 int kernel_del_lsp(zebra_lsp_t *lsp)
  85 {
  86         if (!lsp) // unexpected
  87                 return -1;
  88
  89         if (CHECK_FLAG(lsp->flags, LSP_FLAG_INSTALLED)) {
  90                 netlink_mpls_multipath(RTM_DELROUTE, lsp);
  91                 UNSET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
  92         }
  93
  94         return 0;
  95 }
  96
  97 int mpls_kernel_init(void)
  98 {
  99         struct stat st;
 100
 101         /*
 102          * Check if the MPLS module is loaded in the kernel.
 103          */
 104         if (stat("/proc/sys/net/mpls", &st) != 0)
 105                 return -1;
 106
 107         return 0;
 108 };