eigrpd/eigrp_siareply.c

   1 /*
   2  * EIGRP Sending and Receiving EIGRP SIA-Reply Packets.
   3  * Copyright (C) 2013-2014
   4  * Authors:
   5  *   Donnie Savage
   6  *   Jan Janovic
   7  *   Matej Perina
   8  *   Peter Orsag
   9  *   Peter Paluch
  10  *
  11  * This file is part of GNU Zebra.
  12  *
  13  * GNU Zebra is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License as published by the
  15  * Free Software Foundation; either version 2, or (at your option) any
  16  * later version.
  17  *
  18  * GNU Zebra is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21  * General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License along
  24  * with this program; see the file COPYING; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  26  */
  27 #include <zebra.h>
  28
  29 #include "thread.h"
  30 #include "memory.h"
  31 #include "linklist.h"
  32 #include "prefix.h"
  33 #include "if.h"
  34 #include "table.h"
  35 #include "sockunion.h"
  36 #include "stream.h"
  37 #include "log.h"
  38 #include "sockopt.h"
  39 #include "checksum.h"
  40 #include "md5.h"
  41 #include "vty.h"
  42
  43 #include "eigrpd/eigrp_structs.h"
  44 #include "eigrpd/eigrpd.h"
  45 #include "eigrpd/eigrp_interface.h"
  46 #include "eigrpd/eigrp_neighbor.h"
  47 #include "eigrpd/eigrp_packet.h"
  48 #include "eigrpd/eigrp_zebra.h"
  49 #include "eigrpd/eigrp_vty.h"
  50 #include "eigrpd/eigrp_dump.h"
  51 #include "eigrpd/eigrp_macros.h"
  52 #include "eigrpd/eigrp_topology.h"
  53 #include "eigrpd/eigrp_fsm.h"
  54 #include "eigrpd/eigrp_memory.h"
  55
  56 /*EIGRP SIA-REPLY read function*/
  57 void eigrp_siareply_receive(struct eigrp *eigrp, struct ip *iph,
  58                             struct eigrp_header *eigrph, struct stream *s,
  59                             struct eigrp_interface *ei, int size)
  60 {
  61         struct eigrp_neighbor *nbr;
  62         struct TLV_IPv4_Internal_type *tlv;
  63
  64         uint16_t type;
  65
  66         /* increment statistics. */
  67         ei->siaReply_in++;
  68
  69         /* get neighbor struct */
  70         nbr = eigrp_nbr_get(ei, eigrph, iph);
  71
  72         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
  73         assert(nbr);
  74
  75         nbr->recv_sequence_number = ntohl(eigrph->sequence);
  76
  77         while (s->endp > s->getp) {
  78                 type = stream_getw(s);
  79                 if (type == EIGRP_TLV_IPv4_INT) {
  80                         struct prefix dest_addr;
  81
  82                         stream_set_getp(s, s->getp - sizeof(uint16_t));
  83
  84                         tlv = eigrp_read_ipv4_tlv(s);
  85
  86                         dest_addr.family = AFI_IP;
  87                         dest_addr.u.prefix4 = tlv->destination;
  88                         dest_addr.prefixlen = tlv->prefix_length;
  89                         struct eigrp_prefix_entry *dest =
  90                                 eigrp_topology_table_lookup_ipv4(
  91                                         eigrp->topology_table, &dest_addr);
  92
  93                         /* If the destination exists (it should, but one never
  94                          * know)*/
  95                         if (dest != NULL) {
  96                                 struct eigrp_fsm_action_message msg;
  97                                 struct eigrp_nexthop_entry *entry =
  98                                         eigrp_prefix_entry_lookup(dest->entries,
  99                                                                   nbr);
 100                                 msg.packet_type = EIGRP_OPC_SIAQUERY;
 101                                 msg.eigrp = eigrp;
 102                                 msg.data_type = EIGRP_INT;
 103                                 msg.adv_router = nbr;
 104                                 msg.metrics = tlv->metric;
 105                                 msg.entry = entry;
 106                                 msg.prefix = dest;
 107                                 eigrp_fsm_event(&msg);
 108                         }
 109                         eigrp_IPv4_InternalTLV_free(tlv);
 110                 }
 111         }
 112         eigrp_hello_send_ack(nbr);
 113 }
 114
 115 void eigrp_send_siareply(struct eigrp_neighbor *nbr,
 116                          struct eigrp_prefix_entry *pe)
 117 {
 118         struct eigrp_packet *ep;
 119         uint16_t length = EIGRP_HEADER_LEN;
 120
 121         ep = eigrp_packet_new(EIGRP_PACKET_MTU(nbr->ei->ifp->mtu), nbr);
 122
 123         /* Prepare EIGRP INIT UPDATE header */
 124         eigrp_packet_header_init(EIGRP_OPC_SIAREPLY, nbr->ei->eigrp, ep->s, 0,
 125                                  nbr->ei->eigrp->sequence_number, 0);
 126
 127         // encode Authentication TLV, if needed
 128         if (nbr->ei->params.auth_type == EIGRP_AUTH_TYPE_MD5
 129             && nbr->ei->params.auth_keychain != NULL) {
 130                 length += eigrp_add_authTLV_MD5_to_stream(ep->s, nbr->ei);
 131         }
 132
 133         length += eigrp_add_internalTLV_to_stream(ep->s, pe);
 134
 135         if ((nbr->ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 136             && (nbr->ei->params.auth_keychain != NULL)) {
 137                 eigrp_make_md5_digest(nbr->ei, ep->s, EIGRP_AUTH_UPDATE_FLAG);
 138         }
 139
 140         /* EIGRP Checksum */
 141         eigrp_packet_checksum(nbr->ei, ep->s, length);
 142
 143         ep->length = length;
 144         ep->dst.s_addr = nbr->src.s_addr;
 145
 146         /*This ack number we await from neighbor*/
 147         ep->sequence_number = nbr->ei->eigrp->sequence_number;
 148
 149         if (nbr->state == EIGRP_NEIGHBOR_UP) {
 150                 /*Put packet to retransmission queue*/
 151                 eigrp_fifo_push(nbr->retrans_queue, ep);
 152
 153                 if (nbr->retrans_queue->count == 1) {
 154                         eigrp_send_packet_reliably(nbr);
 155                 }
 156         } else
 157                 eigrp_packet_free(ep);
 158 }