lib/nexthop.c

   1 /* A generic nexthop structure
   2  * Copyright (C) 2013 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 #include <zebra.h>
  21
  22 #include "prefix.h"
  23 #include "table.h"
  24 #include "memory.h"
  25 #include "command.h"
  26 #include "if.h"
  27 #include "log.h"
  28 #include "sockunion.h"
  29 #include "linklist.h"
  30 #include "thread.h"
  31 #include "prefix.h"
  32 #include "nexthop.h"
  33 #include "mpls.h"
  34
  35 DEFINE_MTYPE_STATIC(LIB, NEXTHOP, "Nexthop")
  36 DEFINE_MTYPE_STATIC(LIB, NH_LABEL, "Nexthop label")
  37
  38 /* check if nexthops are same, non-recursive */
  39 int nexthop_same_no_recurse(const struct nexthop *next1,
  40                             const struct nexthop *next2)
  41 {
  42         if (next1->type != next2->type)
  43                 return 0;
  44
  45         switch (next1->type) {
  46         case NEXTHOP_TYPE_IPV4:
  47         case NEXTHOP_TYPE_IPV4_IFINDEX:
  48                 if (!IPV4_ADDR_SAME(&next1->gate.ipv4, &next2->gate.ipv4))
  49                         return 0;
  50                 if (next1->ifindex && (next1->ifindex != next2->ifindex))
  51                         return 0;
  52                 break;
  53         case NEXTHOP_TYPE_IFINDEX:
  54                 if (next1->ifindex != next2->ifindex)
  55                         return 0;
  56                 break;
  57         case NEXTHOP_TYPE_IPV6:
  58                 if (!IPV6_ADDR_SAME(&next1->gate.ipv6, &next2->gate.ipv6))
  59                         return 0;
  60                 break;
  61         case NEXTHOP_TYPE_IPV6_IFINDEX:
  62                 if (!IPV6_ADDR_SAME(&next1->gate.ipv6, &next2->gate.ipv6))
  63                         return 0;
  64                 if (next1->ifindex != next2->ifindex)
  65                         return 0;
  66                 break;
  67         default:
  68                 /* do nothing */
  69                 break;
  70         }
  71         return 1;
  72 }
  73
  74 int
  75 nexthop_same_firsthop (struct nexthop *next1, struct nexthop *next2)
  76 {
  77         int type1 = NEXTHOP_FIRSTHOPTYPE(next1->type);
  78         int type2 = NEXTHOP_FIRSTHOPTYPE(next2->type);
  79
  80         if (type1 != type2)
  81                 return 0;
  82         switch (type1)
  83         {
  84         case NEXTHOP_TYPE_IPV4_IFINDEX:
  85                 if (! IPV4_ADDR_SAME (&next1->gate.ipv4, &next2->gate.ipv4))
  86                         return 0;
  87                 if (next1->ifindex != next2->ifindex)
  88                         return 0;
  89                 break;
  90         case NEXTHOP_TYPE_IFINDEX:
  91                 if (next1->ifindex != next2->ifindex)
  92                         return 0;
  93                 break;
  94         case NEXTHOP_TYPE_IPV6_IFINDEX:
  95                 if (! IPV6_ADDR_SAME (&next1->gate.ipv6, &next2->gate.ipv6))
  96                         return 0;
  97                 if (next1->ifindex != next2->ifindex)
  98                         return 0;
  99                 break;
 100         default:
 101                 /* do nothing */
 102                 break;
 103         }
 104         return 1;
 105 }
 106
 107 /*
 108  * nexthop_type_to_str
 109  */
 110 const char *nexthop_type_to_str(enum nexthop_types_t nh_type)
 111 {
 112         static const char *desc[] = {
 113                 "none",          "Directly connected",
 114                 "IPv4 nexthop",  "IPv4 nexthop with ifindex",
 115                 "IPv6 nexthop",  "IPv6 nexthop with ifindex",
 116                 "Null0 nexthop",
 117         };
 118
 119         return desc[nh_type];
 120 }
 121
 122 /*
 123  * Check if the labels match for the 2 nexthops specified.
 124  */
 125 int nexthop_labels_match(struct nexthop *nh1, struct nexthop *nh2)
 126 {
 127         struct mpls_label_stack *nhl1, *nhl2;
 128
 129         nhl1 = nh1->nh_label;
 130         nhl2 = nh2->nh_label;
 131         if (!nhl1 || !nhl2)
 132                 return 0;
 133
 134         if (nhl1->num_labels != nhl2->num_labels)
 135                 return 0;
 136
 137         if (memcmp(nhl1->label, nhl2->label, nhl1->num_labels))
 138                 return 0;
 139
 140         return 1;
 141 }
 142
 143 struct nexthop *nexthop_new(void)
 144 {
 145         return XCALLOC(MTYPE_NEXTHOP, sizeof(struct nexthop));
 146 }
 147
 148 /* Add nexthop to the end of a nexthop list.  */
 149 void nexthop_add(struct nexthop **target, struct nexthop *nexthop)
 150 {
 151         struct nexthop *last;
 152
 153         for (last = *target; last && last->next; last = last->next)
 154                 ;
 155         if (last)
 156                 last->next = nexthop;
 157         else
 158                 *target = nexthop;
 159         nexthop->prev = last;
 160 }
 161
 162 void copy_nexthops(struct nexthop **tnh, struct nexthop *nh,
 163                    struct nexthop *rparent)
 164 {
 165         struct nexthop *nexthop;
 166         struct nexthop *nh1;
 167
 168         for (nh1 = nh; nh1; nh1 = nh1->next) {
 169                 nexthop = nexthop_new();
 170                 nexthop->vrf_id = nh1->vrf_id;
 171                 nexthop->ifindex = nh1->ifindex;
 172                 nexthop->type = nh1->type;
 173                 nexthop->flags = nh1->flags;
 174                 memcpy(&nexthop->gate, &nh1->gate, sizeof(nh1->gate));
 175                 memcpy(&nexthop->src, &nh1->src, sizeof(nh1->src));
 176                 memcpy(&nexthop->rmap_src, &nh1->rmap_src, sizeof(nh1->rmap_src));
 177                 nexthop->rparent = rparent;
 178                 if (nh1->nh_label)
 179                         nexthop_add_labels(nexthop, nh1->nh_label_type,
 180                                            nh1->nh_label->num_labels,
 181                                            &nh1->nh_label->label[0]);
 182                 nexthop_add(tnh, nexthop);
 183
 184                 if (CHECK_FLAG(nh1->flags, NEXTHOP_FLAG_RECURSIVE))
 185                         copy_nexthops(&nexthop->resolved, nh1->resolved,
 186                                       nexthop);
 187         }
 188 }
 189
 190 /* Free nexthop. */
 191 void nexthop_free(struct nexthop *nexthop)
 192 {
 193         nexthop_del_labels(nexthop);
 194         if (nexthop->resolved)
 195                 nexthops_free(nexthop->resolved);
 196         XFREE(MTYPE_NEXTHOP, nexthop);
 197 }
 198
 199 /* Frees a list of nexthops */
 200 void nexthops_free(struct nexthop *nexthop)
 201 {
 202         struct nexthop *nh, *next;
 203
 204         for (nh = nexthop; nh; nh = next) {
 205                 next = nh->next;
 206                 nexthop_free(nh);
 207         }
 208 }
 209
 210 /* Update nexthop with label information. */
 211 void nexthop_add_labels(struct nexthop *nexthop, enum lsp_types_t type,
 212                         u_int8_t num_labels, mpls_label_t *label)
 213 {
 214         struct mpls_label_stack *nh_label;
 215         int i;
 216
 217         nexthop->nh_label_type = type;
 218         nh_label = XCALLOC(MTYPE_NH_LABEL,
 219                            sizeof(struct mpls_label_stack)
 220                                    + num_labels * sizeof(mpls_label_t));
 221         nh_label->num_labels = num_labels;
 222         for (i = 0; i < num_labels; i++)
 223                 nh_label->label[i] = *(label + i);
 224         nexthop->nh_label = nh_label;
 225 }
 226
 227 /* Free label information of nexthop, if present. */
 228 void nexthop_del_labels(struct nexthop *nexthop)
 229 {
 230         if (nexthop->nh_label) {
 231                 XFREE(MTYPE_NH_LABEL, nexthop->nh_label);
 232                 nexthop->nh_label_type = ZEBRA_LSP_NONE;
 233         }
 234 }
 235
 236 const char *nexthop2str(struct nexthop *nexthop, char *str, int size)
 237 {
 238         switch (nexthop->type) {
 239         case NEXTHOP_TYPE_IFINDEX:
 240                 snprintf(str, size, "if %u", nexthop->ifindex);
 241                 break;
 242         case NEXTHOP_TYPE_IPV4:
 243                 snprintf(str, size, "%s", inet_ntoa(nexthop->gate.ipv4));
 244                 break;
 245         case NEXTHOP_TYPE_IPV4_IFINDEX:
 246                 snprintf(str, size, "%s if %u", inet_ntoa(nexthop->gate.ipv4),
 247                          nexthop->ifindex);
 248                 break;
 249         case NEXTHOP_TYPE_IPV6:
 250                 snprintf(str, size, "%s", inet6_ntoa(nexthop->gate.ipv6));
 251                 break;
 252         case NEXTHOP_TYPE_IPV6_IFINDEX:
 253                 snprintf(str, size, "%s if %u", inet6_ntoa(nexthop->gate.ipv6),
 254                          nexthop->ifindex);
 255                 break;
 256         case NEXTHOP_TYPE_BLACKHOLE:
 257                 snprintf(str, size, "blackhole");
 258                 break;
 259         default:
 260                 snprintf(str, size, "unknown");
 261                 break;
 262         }
 263
 264         return str;
 265 }
 266
 267 /*
 268  * Iteration step for ALL_NEXTHOPS macro:
 269  * This is the tricky part. Check if `nexthop' has
 270  * NEXTHOP_FLAG_RECURSIVE set. If yes, this implies that `nexthop' has
 271  * at least one nexthop attached to `nexthop->resolved', which will be
 272  * the next one.
 273  *
 274  * If NEXTHOP_FLAG_RECURSIVE is not set, `nexthop' will progress in its
 275  * current chain. In case its current chain end is reached, it will move
 276  * upwards in the recursion levels and progress there. Whenever a step
 277  * forward in a chain is done, recursion will be checked again.
 278  * In a nustshell, it's equivalent to a pre-traversal order assuming that
 279  * left branch is 'resolved' and right branch is 'next':
 280  * https://en.wikipedia.org/wiki/Tree_traversal#/media/File:Sorted_binary_tree_preorder.svg
 281  */
 282 struct nexthop *nexthop_next(struct nexthop *nexthop)
 283 {
 284         if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
 285                 return nexthop->resolved;
 286
 287         if (nexthop->next)
 288                 return nexthop->next;
 289
 290         for (struct nexthop *par = nexthop->rparent; par; par = par->rparent)
 291                 if (par->next)
 292                         return par->next;
 293
 294         return NULL;
 295 }
 296
 297 unsigned int nexthop_level(struct nexthop *nexthop)
 298 {
 299         unsigned int rv = 0;
 300
 301         for (struct nexthop *par = nexthop->rparent; par; par = par->rparent)
 302                 rv++;
 303
 304         return rv;
 305 }