ripngd/ripng_nexthop.c

   1 /* RIPngd Zebra
   2  * Copyright (C) 2002 6WIND <vincent.jardin@6wind.com>
   3  *
   4  * This file is part of GNU Zebra.
   5  *
   6  * GNU Zebra 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  * GNU Zebra 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 /* This file is required in order to support properly the RIPng nexthop
  22  * feature.
  23  */
  24
  25 #include <zebra.h>
  26
  27 /* For struct udphdr. */
  28 #include <netinet/udp.h>
  29
  30 #include "linklist.h"
  31 #include "stream.h"
  32 #include "log.h"
  33 #include "memory.h"
  34 #include "vty.h"
  35 #include "if.h"
  36 #include "prefix.h"
  37
  38 #include "ripngd/ripngd.h"
  39 #include "ripngd/ripng_debug.h"
  40 #include "ripngd/ripng_nexthop.h"
  41
  42 #define DEBUG 1
  43
  44 #define min(a, b) ((a) < (b) ? (a) : (b))
  45
  46 struct ripng_rte_data {
  47         struct prefix_ipv6 *p;
  48         struct ripng_info *rinfo;
  49         struct ripng_aggregate *aggregate;
  50 };
  51
  52 void _ripng_rte_del(struct ripng_rte_data *A);
  53 int _ripng_rte_cmp(struct ripng_rte_data *A, struct ripng_rte_data *B);
  54
  55 #define METRIC_OUT(a)                                                          \
  56         ((a)->rinfo ? (a)->rinfo->metric_out : (a)->aggregate->metric_out)
  57 #define NEXTHOP_OUT_PTR(a)                                                     \
  58         ((a)->rinfo ? &((a)->rinfo->nexthop_out)                               \
  59                     : &((a)->aggregate->nexthop_out))
  60 #define TAG_OUT(a) ((a)->rinfo ? (a)->rinfo->tag_out : (a)->aggregate->tag_out)
  61
  62 struct list *ripng_rte_new(void)
  63 {
  64         struct list *rte;
  65
  66         rte = list_new();
  67         rte->cmp = (int (*)(void *, void *))_ripng_rte_cmp;
  68         rte->del = (void (*)(void *))_ripng_rte_del;
  69
  70         return rte;
  71 }
  72
  73 void ripng_rte_free(struct list *ripng_rte_list)
  74 {
  75         list_delete(&ripng_rte_list);
  76 }
  77
  78 /* Delete RTE */
  79 void _ripng_rte_del(struct ripng_rte_data *A)
  80 {
  81         XFREE(MTYPE_RIPNG_RTE_DATA, A);
  82 }
  83
  84 /* Compare RTE:
  85  *  return +  if A > B
  86  *         0  if A = B
  87  *         -  if A < B
  88  */
  89 int _ripng_rte_cmp(struct ripng_rte_data *A, struct ripng_rte_data *B)
  90 {
  91         return addr6_cmp(NEXTHOP_OUT_PTR(A), NEXTHOP_OUT_PTR(B));
  92 }
  93
  94 /* Add routing table entry */
  95 void ripng_rte_add(struct list *ripng_rte_list, struct prefix_ipv6 *p,
  96                    struct ripng_info *rinfo, struct ripng_aggregate *aggregate)
  97 {
  98
  99         struct ripng_rte_data *data;
 100
 101         /* At least one should not be null */
 102         assert(!rinfo || !aggregate);
 103
 104         data = XMALLOC(MTYPE_RIPNG_RTE_DATA, sizeof(*data));
 105         data->p = p;
 106         data->rinfo = rinfo;
 107         data->aggregate = aggregate;
 108
 109         listnode_add_sort(ripng_rte_list, data);
 110 }
 111
 112 /* Send the RTE with the nexthop support
 113  */
 114 void ripng_rte_send(struct list *ripng_rte_list, struct interface *ifp,
 115                     struct sockaddr_in6 *to)
 116 {
 117
 118         struct ripng_rte_data *data;
 119         struct listnode *node, *nnode;
 120
 121         struct in6_addr last_nexthop;
 122         struct in6_addr myself_nexthop;
 123
 124         struct stream *s;
 125         int num;
 126         int mtu;
 127         int rtemax;
 128         int ret;
 129
 130         /* Most of the time, there is no nexthop */
 131         memset(&last_nexthop, 0, sizeof(last_nexthop));
 132
 133         /* Use myself_nexthop if the nexthop is not a link-local address,
 134          * because
 135          * we remain a right path without beeing the optimal one.
 136          */
 137         memset(&myself_nexthop, 0, sizeof(myself_nexthop));
 138
 139         /* Output stream get from ripng structre.  XXX this should be
 140            interface structure. */
 141         s = ripng->obuf;
 142
 143         /* Reset stream and RTE counter. */
 144         stream_reset(s);
 145         num = 0;
 146
 147         mtu = ifp->mtu6;
 148         if (mtu < 0)
 149                 mtu = IFMINMTU;
 150
 151         rtemax = (min(mtu, RIPNG_MAX_PACKET_SIZE) - IPV6_HDRLEN
 152                   - sizeof(struct udphdr) - sizeof(struct ripng_packet)
 153                   + sizeof(struct rte))
 154                  / sizeof(struct rte);
 155
 156         for (ALL_LIST_ELEMENTS(ripng_rte_list, node, nnode, data)) {
 157                 /* (2.1) Next hop support */
 158                 if (!IPV6_ADDR_SAME(&last_nexthop, NEXTHOP_OUT_PTR(data))) {
 159
 160                         /* A nexthop entry should be at least followed by 1 RTE
 161                          */
 162                         if (num == (rtemax - 1)) {
 163                                 ret = ripng_send_packet((caddr_t)STREAM_DATA(s),
 164                                                         stream_get_endp(s), to,
 165                                                         ifp);
 166
 167                                 if (ret >= 0 && IS_RIPNG_DEBUG_SEND)
 168                                         ripng_packet_dump(
 169                                                 (struct ripng_packet *)
 170                                                         STREAM_DATA(s),
 171                                                 stream_get_endp(s), "SEND");
 172                                 num = 0;
 173                                 stream_reset(s);
 174                         }
 175
 176                         /* Add the nexthop (2.1) */
 177
 178                         /* If the received next hop address is not a link-local
 179                          * address,
 180                          * it should be treated as 0:0:0:0:0:0:0:0.
 181                          */
 182                         if (!IN6_IS_ADDR_LINKLOCAL(NEXTHOP_OUT_PTR(data)))
 183                                 last_nexthop = myself_nexthop;
 184                         else
 185                                 last_nexthop = *NEXTHOP_OUT_PTR(data);
 186
 187                         num = ripng_write_rte(num, s, NULL, &last_nexthop, 0,
 188                                               RIPNG_METRIC_NEXTHOP);
 189                 } else {
 190                         /* Rewrite the nexthop for each new packet */
 191                         if ((num == 0)
 192                             && !IPV6_ADDR_SAME(&last_nexthop, &myself_nexthop))
 193                                 num = ripng_write_rte(num, s, NULL,
 194                                                       &last_nexthop, 0,
 195                                                       RIPNG_METRIC_NEXTHOP);
 196                 }
 197                 num = ripng_write_rte(num, s, data->p, NULL, TAG_OUT(data),
 198                                       METRIC_OUT(data));
 199
 200                 if (num == rtemax) {
 201                         ret = ripng_send_packet((caddr_t)STREAM_DATA(s),
 202                                                 stream_get_endp(s), to, ifp);
 203
 204                         if (ret >= 0 && IS_RIPNG_DEBUG_SEND)
 205                                 ripng_packet_dump(
 206                                         (struct ripng_packet *)STREAM_DATA(s),
 207                                         stream_get_endp(s), "SEND");
 208                         num = 0;
 209                         stream_reset(s);
 210                 }
 211         }
 212
 213         /* If unwritten RTE exist, flush it. */
 214         if (num != 0) {
 215                 ret = ripng_send_packet((caddr_t)STREAM_DATA(s),
 216                                         stream_get_endp(s), to, ifp);
 217
 218                 if (ret >= 0 && IS_RIPNG_DEBUG_SEND)
 219                         ripng_packet_dump((struct ripng_packet *)STREAM_DATA(s),
 220                                           stream_get_endp(s), "SEND");
 221                 stream_reset(s);
 222         }
 223 }