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
  23 #ifdef HAVE_NETLINK
  24
  25 #include "zebra/rt.h"
  26 #include "zebra/rt_netlink.h"
  27 #include "zebra/zebra_mpls.h"
  28
  29 /*
  30  * Install Label Forwarding entry into the kernel.
  31  */
  32 int kernel_add_lsp(zebra_lsp_t *lsp)
  33 {
  34         int ret;
  35
  36         if (!lsp || !lsp->best_nhlfe) // unexpected
  37                 return -1;
  38
  39         UNSET_FLAG(lsp->flags, LSP_FLAG_CHANGED);
  40         ret = netlink_mpls_multipath(RTM_NEWROUTE, lsp);
  41         if (!ret)
  42                 SET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
  43         else
  44                 clear_nhlfe_installed(lsp);
  45
  46         return ret;
  47 }
  48
  49 /*
  50  * Update Label Forwarding entry in the kernel. This means that the Label
  51  * forwarding entry is already installed and needs an update - either a new
  52  * path is to be added, an installed path has changed (e.g., outgoing label)
  53  * or an installed path (but not all paths) has to be removed.
  54  * TODO: Performs a DEL followed by ADD now, need to change to REPLACE. Note
  55  * that REPLACE was originally implemented for IPv4 nexthops but removed as
  56  * it was not functioning when moving from swap to PHP as that was signaled
  57  * through the metric field (before kernel-MPLS). This shouldn't be an issue
  58  * any longer, so REPLACE can be reintroduced.
  59  */
  60 int 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 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                 netlink_mpls_multipath(RTM_DELROUTE, lsp);
  93                 UNSET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
  94         }
  95
  96         return 0;
  97 }
  98
  99 int mpls_kernel_init(void)
 100 {
 101         struct stat st;
 102
 103         /*
 104          * Check if the MPLS module is loaded in the kernel.
 105          */
 106         if (stat("/proc/sys/net/mpls", &st) != 0)
 107                 return -1;
 108
 109         return 0;
 110 };
 111
 112 #endif /* HAVE_NETLINK */