eigrpd/eigrp_reply.c

   1 /*
   2  * Eigrp Sending and Receiving EIGRP Reply Packets.
   3  * Copyright (C) 2013-2016
   4  * Authors:
   5  *   Donnie Savage
   6  *   Jan Janovic
   7  *   Matej Perina
   8  *   Peter Orsag
   9  *   Peter Paluch
  10  *   Frantisek Gazo
  11  *   Tomas Hvorkovy
  12  *   Martin Kontsek
  13  *   Lukas Koribsky
  14  *
  15  * This file is part of GNU Zebra.
  16  *
  17  * GNU Zebra is free software; you can redistribute it and/or modify it
  18  * under the terms of the GNU General Public License as published by the
  19  * Free Software Foundation; either version 2, or (at your option) any
  20  * later version.
  21  *
  22  * GNU Zebra is distributed in the hope that it will be useful, but
  23  * WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25  * General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License along
  28  * with this program; see the file COPYING; if not, write to the Free Software
  29  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  30  */
  31
  32 #include <zebra.h>
  33
  34 #include "thread.h"
  35 #include "memory.h"
  36 #include "linklist.h"
  37 #include "prefix.h"
  38 #include "if.h"
  39 #include "table.h"
  40 #include "sockunion.h"
  41 #include "stream.h"
  42 #include "log.h"
  43 #include "sockopt.h"
  44 #include "checksum.h"
  45 #include "md5.h"
  46 #include "vty.h"
  47 #include "keychain.h"
  48 #include "plist.h"
  49
  50 #include "eigrpd/eigrp_structs.h"
  51 #include "eigrpd/eigrpd.h"
  52 #include "eigrpd/eigrp_interface.h"
  53 #include "eigrpd/eigrp_neighbor.h"
  54 #include "eigrpd/eigrp_packet.h"
  55 #include "eigrpd/eigrp_zebra.h"
  56 #include "eigrpd/eigrp_vty.h"
  57 #include "eigrpd/eigrp_dump.h"
  58 #include "eigrpd/eigrp_macros.h"
  59 #include "eigrpd/eigrp_topology.h"
  60 #include "eigrpd/eigrp_fsm.h"
  61 #include "eigrpd/eigrp_memory.h"
  62
  63 void eigrp_send_reply(struct eigrp_neighbor *nbr, struct eigrp_prefix_entry *pe)
  64 {
  65         struct eigrp_packet *ep;
  66         u_int16_t length = EIGRP_HEADER_LEN;
  67         struct eigrp_interface *ei = nbr->ei;
  68         struct eigrp *eigrp = ei->eigrp;
  69         struct eigrp_prefix_entry *pe2;
  70
  71         // TODO: Work in progress
  72         /* Filtering */
  73         /* get list from eigrp process */
  74         pe2 = XCALLOC(MTYPE_EIGRP_PREFIX_ENTRY,
  75                       sizeof(struct eigrp_prefix_entry));
  76         memcpy(pe2, pe, sizeof(struct eigrp_prefix_entry));
  77
  78         if (eigrp_update_prefix_apply(eigrp, ei,
  79                                       EIGRP_FILTER_OUT,
  80                                       pe2->destination)) {
  81                 zlog_info("REPLY SEND: Setting Metric to max");
  82                 pe2->reported_metric.delay = EIGRP_MAX_METRIC;
  83
  84         }
  85
  86         /*
  87          * End of filtering
  88          */
  89
  90         ep = eigrp_packet_new(ei->ifp->mtu, nbr);
  91
  92         /* Prepare EIGRP INIT UPDATE header */
  93         eigrp_packet_header_init(EIGRP_OPC_REPLY, eigrp, ep->s, 0,
  94                                  eigrp->sequence_number, 0);
  95
  96         // encode Authentication TLV, if needed
  97         if (ei->params.auth_type == EIGRP_AUTH_TYPE_MD5
  98             && (ei->params.auth_keychain != NULL)) {
  99                 length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
 100         }
 101
 102
 103         length += eigrp_add_internalTLV_to_stream(ep->s, pe2);
 104
 105         if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 106             && (ei->params.auth_keychain != NULL)) {
 107                 eigrp_make_md5_digest(ei, ep->s, EIGRP_AUTH_UPDATE_FLAG);
 108         }
 109
 110         /* EIGRP Checksum */
 111         eigrp_packet_checksum(ei, ep->s, length);
 112
 113         ep->length = length;
 114         ep->dst.s_addr = nbr->src.s_addr;
 115
 116         /*This ack number we await from neighbor*/
 117         ep->sequence_number = eigrp->sequence_number;
 118
 119         /*Put packet to retransmission queue*/
 120         eigrp_fifo_push(nbr->retrans_queue, ep);
 121
 122         if (nbr->retrans_queue->count == 1) {
 123                 eigrp_send_packet_reliably(nbr);
 124         }
 125
 126         XFREE(MTYPE_EIGRP_PREFIX_ENTRY, pe2);
 127 }
 128
 129 /*EIGRP REPLY read function*/
 130 void eigrp_reply_receive(struct eigrp *eigrp, struct ip *iph,
 131                          struct eigrp_header *eigrph, struct stream *s,
 132                          struct eigrp_interface *ei, int size)
 133 {
 134         struct eigrp_neighbor *nbr;
 135         struct TLV_IPv4_Internal_type *tlv;
 136
 137         u_int16_t type;
 138
 139         /* increment statistics. */
 140         ei->reply_in++;
 141
 142         /* get neighbor struct */
 143         nbr = eigrp_nbr_get(ei, eigrph, iph);
 144
 145         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 146         assert(nbr);
 147
 148         nbr->recv_sequence_number = ntohl(eigrph->sequence);
 149
 150         while (s->endp > s->getp) {
 151                 type = stream_getw(s);
 152
 153                 if (type != EIGRP_TLV_IPv4_INT)
 154                         continue;
 155
 156                 struct prefix dest_addr;
 157
 158                 stream_set_getp(s, s->getp - sizeof(u_int16_t));
 159
 160                 tlv = eigrp_read_ipv4_tlv(s);
 161
 162                 dest_addr.family = AF_INET;
 163                 dest_addr.u.prefix4 = tlv->destination;
 164                 dest_addr.prefixlen = tlv->prefix_length;
 165                 struct eigrp_prefix_entry *dest =
 166                         eigrp_topology_table_lookup_ipv4(
 167                                 eigrp->topology_table, &dest_addr);
 168                 /*
 169                  * Destination must exists
 170                  */
 171                 if (!dest) {
 172                         char buf[PREFIX_STRLEN];
 173                         zlog_err("%s: Received prefix %s which we do not know about",
 174                                  __PRETTY_FUNCTION__,
 175                                  prefix2str(&dest_addr, buf, strlen(buf)));
 176                         continue;
 177                 }
 178
 179                 struct eigrp_fsm_action_message msg;
 180                 struct eigrp_nexthop_entry *entry =
 181                         eigrp_prefix_entry_lookup(dest->entries, nbr);
 182
 183                 if (eigrp_update_prefix_apply(eigrp, ei,
 184                                               EIGRP_FILTER_IN,
 185                                               &dest_addr)) {
 186                         tlv->metric.delay = EIGRP_MAX_METRIC;
 187                 }
 188                 /*
 189                  * End of filtering
 190                  */
 191
 192                 msg.packet_type = EIGRP_OPC_REPLY;
 193                 msg.eigrp = eigrp;
 194                 msg.data_type = EIGRP_INT;
 195                 msg.adv_router = nbr;
 196                 msg.metrics = tlv->metric;
 197                 msg.entry = entry;
 198                 msg.prefix = dest;
 199                 eigrp_fsm_event(&msg);
 200
 201                 eigrp_IPv4_InternalTLV_free(tlv);
 202         }
 203         eigrp_hello_send_ack(nbr);
 204 }