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 /*
  75  * nexthop_type_to_str
  76  */
  77 const char *nexthop_type_to_str(enum nexthop_types_t nh_type)
  78 {
  79         static const char *desc[] = {
  80                 "none",          "Directly connected",
  81                 "IPv4 nexthop",  "IPv4 nexthop with ifindex",
  82                 "IPv6 nexthop",  "IPv6 nexthop with ifindex",
  83                 "Null0 nexthop",
  84         };
  85
  86         return desc[nh_type];
  87 }
  88
  89 /*
  90  * Check if the labels match for the 2 nexthops specified.
  91  */
  92 int nexthop_labels_match(struct nexthop *nh1, struct nexthop *nh2)
  93 {
  94         struct nexthop_label *nhl1, *nhl2;
  95
  96         nhl1 = nh1->nh_label;
  97         nhl2 = nh2->nh_label;
  98         if ((nhl1 && !nhl2) || (!nhl1 && nhl2))
  99                 return 0;
 100
 101         if (nhl1->num_labels != nhl2->num_labels)
 102                 return 0;
 103
 104         if (memcmp(nhl1->label, nhl2->label, nhl1->num_labels))
 105                 return 0;
 106
 107         return 1;
 108 }
 109
 110 struct nexthop *nexthop_new(void)
 111 {
 112         return XCALLOC(MTYPE_NEXTHOP, sizeof(struct nexthop));
 113 }
 114
 115 /* Add nexthop to the end of a nexthop list.  */
 116 void nexthop_add(struct nexthop **target, struct nexthop *nexthop)
 117 {
 118         struct nexthop *last;
 119
 120         for (last = *target; last && last->next; last = last->next)
 121                 ;
 122         if (last)
 123                 last->next = nexthop;
 124         else
 125                 *target = nexthop;
 126         nexthop->prev = last;
 127 }
 128
 129 void copy_nexthops(struct nexthop **tnh, struct nexthop *nh,
 130                    struct nexthop *rparent)
 131 {
 132         struct nexthop *nexthop;
 133         struct nexthop *nh1;
 134
 135         for (nh1 = nh; nh1; nh1 = nh1->next) {
 136                 nexthop = nexthop_new();
 137                 nexthop->ifindex = nh1->ifindex;
 138                 nexthop->type = nh1->type;
 139                 nexthop->flags = nh1->flags;
 140                 memcpy(&nexthop->gate, &nh1->gate, sizeof(nh1->gate));
 141                 memcpy(&nexthop->src, &nh1->src, sizeof(nh1->src));
 142                 memcpy(&nexthop->rmap_src, &nh1->rmap_src, sizeof(nh1->rmap_src));
 143                 nexthop->rparent = rparent;
 144                 if (nh1->nh_label)
 145                         nexthop_add_labels(nexthop, nh1->nh_label_type,
 146                                            nh1->nh_label->num_labels,
 147                                            &nh1->nh_label->label[0]);
 148                 nexthop_add(tnh, nexthop);
 149
 150                 if (CHECK_FLAG(nh1->flags, NEXTHOP_FLAG_RECURSIVE))
 151                         copy_nexthops(&nexthop->resolved, nh1->resolved,
 152                                       nexthop);
 153         }
 154 }
 155
 156 /* Free nexthop. */
 157 void nexthop_free(struct nexthop *nexthop)
 158 {
 159         nexthop_del_labels(nexthop);
 160         if (nexthop->resolved)
 161                 nexthops_free(nexthop->resolved);
 162         XFREE(MTYPE_NEXTHOP, nexthop);
 163 }
 164
 165 /* Frees a list of nexthops */
 166 void nexthops_free(struct nexthop *nexthop)
 167 {
 168         struct nexthop *nh, *next;
 169
 170         for (nh = nexthop; nh; nh = next) {
 171                 next = nh->next;
 172                 nexthop_free(nh);
 173         }
 174 }
 175
 176 /* Update nexthop with label information. */
 177 void nexthop_add_labels(struct nexthop *nexthop, enum lsp_types_t type,
 178                         u_int8_t num_labels, mpls_label_t *label)
 179 {
 180         struct nexthop_label *nh_label;
 181         int i;
 182
 183         nexthop->nh_label_type = type;
 184         nh_label = XCALLOC(MTYPE_NH_LABEL,
 185                            sizeof(struct nexthop_label)
 186                                    + num_labels * sizeof(mpls_label_t));
 187         nh_label->num_labels = num_labels;
 188         for (i = 0; i < num_labels; i++)
 189                 nh_label->label[i] = *(label + i);
 190         nexthop->nh_label = nh_label;
 191 }
 192
 193 /* Free label information of nexthop, if present. */
 194 void nexthop_del_labels(struct nexthop *nexthop)
 195 {
 196         if (nexthop->nh_label) {
 197                 XFREE(MTYPE_NH_LABEL, nexthop->nh_label);
 198                 nexthop->nh_label_type = ZEBRA_LSP_NONE;
 199         }
 200 }
 201
 202 const char *nexthop2str(struct nexthop *nexthop, char *str, int size)
 203 {
 204         switch (nexthop->type) {
 205         case NEXTHOP_TYPE_IFINDEX:
 206                 snprintf(str, size, "if %u", nexthop->ifindex);
 207                 break;
 208         case NEXTHOP_TYPE_IPV4:
 209                 snprintf(str, size, "%s", inet_ntoa(nexthop->gate.ipv4));
 210                 break;
 211         case NEXTHOP_TYPE_IPV4_IFINDEX:
 212                 snprintf(str, size, "%s if %u", inet_ntoa(nexthop->gate.ipv4),
 213                          nexthop->ifindex);
 214                 break;
 215         case NEXTHOP_TYPE_IPV6:
 216                 snprintf(str, size, "%s", inet6_ntoa(nexthop->gate.ipv6));
 217                 break;
 218         case NEXTHOP_TYPE_IPV6_IFINDEX:
 219                 snprintf(str, size, "%s if %u", inet6_ntoa(nexthop->gate.ipv6),
 220                          nexthop->ifindex);
 221                 break;
 222         case NEXTHOP_TYPE_BLACKHOLE:
 223                 snprintf(str, size, "blackhole");
 224                 break;
 225         default:
 226                 snprintf(str, size, "unknown");
 227                 break;
 228         }
 229
 230         return str;
 231 }
 232
 233 /*
 234  * Iteration step for ALL_NEXTHOPS macro:
 235  * This is the tricky part. Check if `nexthop' has
 236  * NEXTHOP_FLAG_RECURSIVE set. If yes, this implies that `nexthop' has
 237  * at least one nexthop attached to `nexthop->resolved', which will be
 238  * the next one.
 239  *
 240  * If NEXTHOP_FLAG_RECURSIVE is not set, `nexthop' will progress in its
 241  * current chain. In case its current chain end is reached, it will move
 242  * upwards in the recursion levels and progress there. Whenever a step
 243  * forward in a chain is done, recursion will be checked again.
 244  * In a nustshell, it's equivalent to a pre-traversal order assuming that
 245  * left branch is 'resolved' and right branch is 'next':
 246  * https://en.wikipedia.org/wiki/Tree_traversal#/media/File:Sorted_binary_tree_preorder.svg
 247  */
 248 struct nexthop *nexthop_next(struct nexthop *nexthop)
 249 {
 250         if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
 251                 return nexthop->resolved;
 252
 253         if (nexthop->next)
 254                 return nexthop->next;
 255
 256         for (struct nexthop *par = nexthop->rparent; par; par = par->rparent)
 257                 if (par->next)
 258                         return par->next;
 259
 260         return NULL;
 261 }
 262
 263 unsigned int nexthop_level(struct nexthop *nexthop)
 264 {
 265         unsigned int rv = 0;
 266
 267         for (struct nexthop *par = nexthop->rparent; par; par = par->rparent)
 268                 rv++;
 269
 270         return rv;
 271 }