zebra/zebra_pw.c

   1 /* Zebra PW code
   2  * Copyright (C) 2016 Volta Networks, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; see the file COPYING; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  17  * MA 02110-1301 USA
  18  */
  19
  20 #include <zebra.h>
  21
  22 #include "log.h"
  23 #include "memory.h"
  24 #include "thread.h"
  25 #include "vrf.h"
  26
  27 #include "zebra/debug.h"
  28 #include "zebra/rib.h"
  29 #include "zebra/zserv.h"
  30 #include "zebra/zebra_vrf.h"
  31 #include "zebra/zebra_pw.h"
  32
  33 DEFINE_MTYPE_STATIC(LIB, PW, "Pseudowire")
  34
  35 DEFINE_HOOK(pw_install, (struct zebra_pw *pw), (pw))
  36 DEFINE_HOOK(pw_uninstall, (struct zebra_pw *pw), (pw))
  37
  38 extern struct zebra_t zebrad;
  39
  40 static void zebra_pw_install(struct zebra_pw *);
  41 static void zebra_pw_uninstall(struct zebra_pw *);
  42 static int zebra_pw_install_retry(struct thread *);
  43 static int zebra_pw_check_reachability(struct zebra_pw *);
  44 static void zebra_pw_update_status(struct zebra_pw *, int);
  45
  46 static inline int zebra_pw_compare(const struct zebra_pw *a,
  47                                      const struct zebra_pw *b)
  48 {
  49         return (strcmp(a->ifname, b->ifname));
  50 }
  51
  52 RB_GENERATE(zebra_pw_head, zebra_pw, entry, zebra_pw_compare)
  53
  54 struct zebra_pw *zebra_pw_add(struct zebra_vrf *zvrf, const char *ifname,
  55                               uint8_t protocol, struct zserv *client)
  56 {
  57         struct zebra_pw *pw;
  58
  59         if (IS_ZEBRA_DEBUG_PW)
  60                 zlog_debug("%u: adding pseudowire %s protocol %s",
  61                            zvrf_id(zvrf), ifname, zebra_route_string(protocol));
  62
  63         pw = XCALLOC(MTYPE_PW, sizeof(*pw));
  64         strlcpy(pw->ifname, ifname, sizeof(pw->ifname));
  65         pw->protocol = protocol;
  66         pw->vrf_id = zvrf_id(zvrf);
  67         pw->client = client;
  68         pw->status = PW_STATUS_UP;
  69
  70         RB_INSERT(zebra_pw_head, &zvrf->pseudowires, pw);
  71
  72         return pw;
  73 }
  74
  75 void zebra_pw_del(struct zebra_vrf *zvrf, struct zebra_pw *pw)
  76 {
  77         if (IS_ZEBRA_DEBUG_PW)
  78                 zlog_debug("%u: deleting pseudowire %s protocol %s", pw->vrf_id,
  79                            pw->ifname, zebra_route_string(pw->protocol));
  80
  81         /* uninstall */
  82         if (pw->status == PW_STATUS_UP)
  83                 hook_call(pw_uninstall, pw);
  84         else if (pw->install_retry_timer)
  85                 THREAD_TIMER_OFF(pw->install_retry_timer);
  86
  87         /* unlink and release memory */
  88         RB_REMOVE(zebra_pw_head, &zvrf->pseudowires, pw);
  89         XFREE(MTYPE_PW, pw);
  90 }
  91
  92 void zebra_pw_change(struct zebra_pw *pw, ifindex_t ifindex, int type, int af,
  93                      union g_addr *nexthop, uint32_t local_label,
  94                      uint32_t remote_label, uint8_t flags,
  95                      union pw_protocol_fields *data)
  96 {
  97         pw->ifindex = ifindex;
  98         pw->type = type;
  99         pw->af = af;
 100         pw->nexthop = *nexthop;
 101         pw->local_label = local_label;
 102         pw->remote_label = remote_label;
 103         pw->flags = flags;
 104         pw->data = *data;
 105
 106         if (pw->enabled)
 107                 zebra_pw_update(pw);
 108         else
 109                 zebra_pw_uninstall(pw);
 110 }
 111
 112 struct zebra_pw *zebra_pw_find(struct zebra_vrf *zvrf, const char *ifname)
 113 {
 114         struct zebra_pw pw;
 115         strlcpy(pw.ifname, ifname, sizeof(pw.ifname));
 116         return (RB_FIND(zebra_pw_head, &zvrf->pseudowires, &pw));
 117 }
 118
 119 void zebra_pw_update(struct zebra_pw *pw)
 120 {
 121         if (zebra_pw_check_reachability(pw) < 0) {
 122                 zebra_pw_uninstall(pw);
 123         } else {
 124                 /*
 125                  * Install or reinstall the pseudowire (e.g. to update
 126                  * parameters like the nexthop or the use of the control word).
 127                  */
 128                 zebra_pw_install(pw);
 129         }
 130 }
 131
 132 static void zebra_pw_install(struct zebra_pw *pw)
 133 {
 134         if (IS_ZEBRA_DEBUG_PW)
 135                 zlog_debug("%u: installing pseudowire %s protocol %s",
 136                            pw->vrf_id, pw->ifname,
 137                            zebra_route_string(pw->protocol));
 138
 139         if (hook_call(pw_install, pw)) {
 140                 zebra_pw_install_failure(pw);
 141                 return;
 142         }
 143
 144         if (pw->status == PW_STATUS_DOWN)
 145                 zebra_pw_update_status(pw, PW_STATUS_UP);
 146 }
 147
 148 static void zebra_pw_uninstall(struct zebra_pw *pw)
 149 {
 150         if (pw->status == PW_STATUS_DOWN)
 151                 return;
 152
 153         if (IS_ZEBRA_DEBUG_PW)
 154                 zlog_debug("%u: uninstalling pseudowire %s protocol %s",
 155                            pw->vrf_id, pw->ifname,
 156                            zebra_route_string(pw->protocol));
 157
 158         /* ignore any possible error */
 159         hook_call(pw_uninstall, pw);
 160
 161         if (pw->enabled)
 162                 zebra_pw_update_status(pw, PW_STATUS_DOWN);
 163 }
 164
 165 /*
 166  * Installation of the pseudowire in the kernel or hardware has failed. This
 167  * function will notify the pseudowire client about the failure and schedule
 168  * to retry the installation later. This function can be called by an external
 169  * agent that performs the pseudowire installation in an asynchronous way.
 170  */
 171 void zebra_pw_install_failure(struct zebra_pw *pw)
 172 {
 173         if (IS_ZEBRA_DEBUG_PW)
 174                 zlog_debug("%u: failed installing pseudowire %s, "
 175                            "scheduling retry in %u seconds", pw->vrf_id,
 176                            pw->ifname, PW_INSTALL_RETRY_INTERVAL);
 177
 178         /* schedule to retry later */
 179         THREAD_TIMER_OFF(pw->install_retry_timer);
 180         pw->install_retry_timer =
 181                 thread_add_timer(zebrad.master, zebra_pw_install_retry,
 182                 pw, PW_INSTALL_RETRY_INTERVAL);
 183
 184         zebra_pw_update_status(pw, PW_STATUS_DOWN);
 185 }
 186
 187 static int zebra_pw_install_retry(struct thread *thread)
 188 {
 189         struct zebra_pw *pw = THREAD_ARG(thread);
 190
 191         pw->install_retry_timer = NULL;
 192         zebra_pw_install(pw);
 193
 194         return 0;
 195 }
 196
 197 static void zebra_pw_update_status(struct zebra_pw *pw, int status)
 198 {
 199         pw->status = status;
 200         if (pw->client)
 201                 zsend_pw_update(pw->client, pw);
 202 }
 203
 204 static int zebra_pw_check_reachability(struct zebra_pw *pw)
 205 {
 206         struct rib *rib;
 207         struct nexthop *nexthop, *tnexthop;
 208         int recursing;
 209
 210         /* TODO: consider GRE/L2TPv3 tunnels in addition to MPLS LSPs */
 211
 212         /* find route to the remote end of the pseudowire */
 213         rib = rib_match(family2afi(pw->af), SAFI_UNICAST, pw->vrf_id,
 214                         &pw->nexthop, NULL);
 215         if (!rib) {
 216                 if (IS_ZEBRA_DEBUG_PW)
 217                         zlog_warn("%s: no route found for %s", __func__,
 218                                   pw->ifname);
 219                 return -1;
 220         }
 221
 222         /*
 223          * Need to ensure that there's a label binding for all nexthops.
 224          * Otherwise, ECMP for this route could render the pseudowire unusable.
 225          */
 226         for (ALL_NEXTHOPS_RO(rib->nexthop, nexthop, tnexthop, recursing)) {
 227                 if (!nexthop->nh_label) {
 228                         if (IS_ZEBRA_DEBUG_PW)
 229                                 zlog_warn("%s: unlabeled route for %s",
 230                                     __func__, pw->ifname);
 231                         return -1;
 232                 }
 233         }
 234
 235         return 0;
 236 }
 237
 238 void
 239 zebra_pw_client_close(struct zserv *client)
 240 {
 241         struct vrf *vrf;
 242         struct zebra_vrf *zvrf;
 243         struct zebra_pw *pw, *tmp;
 244
 245         RB_FOREACH(vrf, vrf_id_head, &vrfs_by_id) {
 246                 zvrf = vrf->info;
 247                 RB_FOREACH_SAFE(pw, zebra_pw_head, &zvrf->pseudowires, tmp) {
 248                         if (pw->client != client)
 249                                 continue;
 250                         zebra_pw_del(zvrf, pw);
 251                 }
 252         }
 253 }
 254
 255 void zebra_pw_init(struct zebra_vrf *zvrf)
 256 {
 257         RB_INIT(&zvrf->pseudowires);
 258 }
 259
 260 void zebra_pw_exit(struct zebra_vrf *zvrf)
 261 {
 262         struct zebra_pw *pw;
 263
 264         while ((pw = RB_ROOT(&zvrf->pseudowires)) != NULL)
 265                 zebra_pw_del(zvrf, pw);
 266 }