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
  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         zebra_nhlfe_t *nhlfe;
  62         struct nexthop *nexthop;
  63
  64         if (!lsp || !lsp->best_nhlfe) // unexpected
  65                 return -1;
  66
  67         UNSET_FLAG(lsp->flags, LSP_FLAG_CHANGED);
  68
  69         /* Any NHLFE that was installed but is not selected now needs to
  70          * have its flags updated.
  71          */
  72         for (nhlfe = lsp->nhlfe_list; nhlfe; nhlfe = nhlfe->next) {
  73                 nexthop = nhlfe->nexthop;
  74                 if (!nexthop)
  75                         continue;
  76
  77                 if (CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_INSTALLED) &&
  78                     !CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_SELECTED)) {
  79                         UNSET_FLAG(nhlfe->flags, NHLFE_FLAG_INSTALLED);
  80                         UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
  81                 }
  82         }
  83
  84         ret = netlink_mpls_multipath(RTM_NEWROUTE, lsp);
  85         if (!ret)
  86                 SET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
  87
  88         return ret;
  89 }
  90
  91 /*
  92  * Delete Label Forwarding entry from the kernel.
  93  */
  94 int kernel_del_lsp(zebra_lsp_t *lsp)
  95 {
  96         if (!lsp) // unexpected
  97                 return -1;
  98
  99         if (CHECK_FLAG(lsp->flags, LSP_FLAG_INSTALLED)) {
 100                 netlink_mpls_multipath(RTM_DELROUTE, lsp);
 101                 UNSET_FLAG(lsp->flags, LSP_FLAG_INSTALLED);
 102         }
 103
 104         return 0;
 105 }
 106
 107 int mpls_kernel_init(void)
 108 {
 109         struct stat st;
 110
 111         /*
 112          * Check if the MPLS module is loaded in the kernel.
 113          */
 114         if (stat("/proc/sys/net/mpls", &st) != 0)
 115                 return -1;
 116
 117         return 0;
 118 };
 119
 120 #endif /* HAVE_NETLINK */