eigrpd/eigrp_reply.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Eigrp Sending and Receiving EIGRP Reply Packets.
   4  * Copyright (C) 2013-2016
   5  * Authors:
   6  *   Donnie Savage
   7  *   Jan Janovic
   8  *   Matej Perina
   9  *   Peter Orsag
  10  *   Peter Paluch
  11  *   Frantisek Gazo
  12  *   Tomas Hvorkovy
  13  *   Martin Kontsek
  14  *   Lukas Koribsky
  15  */
  16
  17 #include <zebra.h>
  18
  19 #include "thread.h"
  20 #include "memory.h"
  21 #include "linklist.h"
  22 #include "prefix.h"
  23 #include "if.h"
  24 #include "table.h"
  25 #include "sockunion.h"
  26 #include "stream.h"
  27 #include "log.h"
  28 #include "sockopt.h"
  29 #include "checksum.h"
  30 #include "md5.h"
  31 #include "vty.h"
  32 #include "keychain.h"
  33 #include "plist.h"
  34
  35 #include "eigrpd/eigrp_structs.h"
  36 #include "eigrpd/eigrpd.h"
  37 #include "eigrpd/eigrp_interface.h"
  38 #include "eigrpd/eigrp_neighbor.h"
  39 #include "eigrpd/eigrp_packet.h"
  40 #include "eigrpd/eigrp_zebra.h"
  41 #include "eigrpd/eigrp_vty.h"
  42 #include "eigrpd/eigrp_dump.h"
  43 #include "eigrpd/eigrp_macros.h"
  44 #include "eigrpd/eigrp_topology.h"
  45 #include "eigrpd/eigrp_fsm.h"
  46 #include "eigrpd/eigrp_errors.h"
  47
  48 void eigrp_send_reply(struct eigrp_neighbor *nbr,
  49                       struct eigrp_prefix_descriptor *pe)
  50 {
  51         struct eigrp_packet *ep;
  52         uint16_t length = EIGRP_HEADER_LEN;
  53         struct eigrp_interface *ei = nbr->ei;
  54         struct eigrp *eigrp = ei->eigrp;
  55         struct eigrp_prefix_descriptor *pe2;
  56
  57         // TODO: Work in progress
  58         /* Filtering */
  59         /* get list from eigrp process */
  60         pe2 = XCALLOC(MTYPE_EIGRP_PREFIX_DESCRIPTOR,
  61                       sizeof(struct eigrp_prefix_descriptor));
  62         memcpy(pe2, pe, sizeof(struct eigrp_prefix_descriptor));
  63
  64         if (eigrp_update_prefix_apply(eigrp, ei, EIGRP_FILTER_OUT,
  65                                       pe2->destination)) {
  66                 zlog_info("REPLY SEND: Setting Metric to max");
  67                 pe2->reported_metric.delay = EIGRP_MAX_METRIC;
  68         }
  69
  70         /*
  71          * End of filtering
  72          */
  73
  74         ep = eigrp_packet_new(EIGRP_PACKET_MTU(ei->ifp->mtu), nbr);
  75
  76         /* Prepare EIGRP INIT UPDATE header */
  77         eigrp_packet_header_init(EIGRP_OPC_REPLY, eigrp, ep->s, 0,
  78                                  eigrp->sequence_number, 0);
  79
  80         // encode Authentication TLV, if needed
  81         if (ei->params.auth_type == EIGRP_AUTH_TYPE_MD5
  82             && (ei->params.auth_keychain != NULL)) {
  83                 length += eigrp_add_authTLV_MD5_to_stream(ep->s, ei);
  84         }
  85
  86
  87         length += eigrp_add_internalTLV_to_stream(ep->s, pe2);
  88
  89         if ((ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
  90             && (ei->params.auth_keychain != NULL)) {
  91                 eigrp_make_md5_digest(ei, ep->s, EIGRP_AUTH_UPDATE_FLAG);
  92         }
  93
  94         /* EIGRP Checksum */
  95         eigrp_packet_checksum(ei, ep->s, length);
  96
  97         ep->length = length;
  98         ep->dst.s_addr = nbr->src.s_addr;
  99
 100         /*This ack number we await from neighbor*/
 101         ep->sequence_number = eigrp->sequence_number;
 102
 103         /*Put packet to retransmission queue*/
 104         eigrp_fifo_push(nbr->retrans_queue, ep);
 105
 106         if (nbr->retrans_queue->count == 1) {
 107                 eigrp_send_packet_reliably(nbr);
 108         }
 109
 110         XFREE(MTYPE_EIGRP_PREFIX_DESCRIPTOR, pe2);
 111 }
 112
 113 /*EIGRP REPLY read function*/
 114 void eigrp_reply_receive(struct eigrp *eigrp, struct ip *iph,
 115                          struct eigrp_header *eigrph, struct stream *s,
 116                          struct eigrp_interface *ei, int size)
 117 {
 118         struct eigrp_neighbor *nbr;
 119         struct TLV_IPv4_Internal_type *tlv;
 120
 121         uint16_t type;
 122
 123         /* increment statistics. */
 124         ei->reply_in++;
 125
 126         /* get neighbor struct */
 127         nbr = eigrp_nbr_get(ei, eigrph, iph);
 128
 129         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
 130         assert(nbr);
 131
 132         nbr->recv_sequence_number = ntohl(eigrph->sequence);
 133
 134         while (s->endp > s->getp) {
 135                 type = stream_getw(s);
 136
 137                 if (type != EIGRP_TLV_IPv4_INT)
 138                         continue;
 139
 140                 struct prefix dest_addr;
 141
 142                 stream_set_getp(s, s->getp - sizeof(uint16_t));
 143
 144                 tlv = eigrp_read_ipv4_tlv(s);
 145
 146                 dest_addr.family = AF_INET;
 147                 dest_addr.u.prefix4 = tlv->destination;
 148                 dest_addr.prefixlen = tlv->prefix_length;
 149                 struct eigrp_prefix_descriptor *dest =
 150                         eigrp_topology_table_lookup_ipv4(eigrp->topology_table,
 151                                                          &dest_addr);
 152                 /*
 153                  * Destination must exists
 154                  */
 155                 if (!dest) {
 156                         flog_err(
 157                                 EC_EIGRP_PACKET,
 158                                 "%s: Received prefix %pFX which we do not know about",
 159                                 __func__, &dest_addr);
 160                         eigrp_IPv4_InternalTLV_free(tlv);
 161                         continue;
 162                 }
 163
 164                 struct eigrp_fsm_action_message msg;
 165                 struct eigrp_route_descriptor *entry =
 166                         eigrp_route_descriptor_lookup(dest->entries, nbr);
 167
 168                 if (eigrp_update_prefix_apply(eigrp, ei, EIGRP_FILTER_IN,
 169                                               &dest_addr)) {
 170                         tlv->metric.delay = EIGRP_MAX_METRIC;
 171                 }
 172                 /*
 173                  * End of filtering
 174                  */
 175
 176                 msg.packet_type = EIGRP_OPC_REPLY;
 177                 msg.eigrp = eigrp;
 178                 msg.data_type = EIGRP_INT;
 179                 msg.adv_router = nbr;
 180                 msg.metrics = tlv->metric;
 181                 msg.entry = entry;
 182                 msg.prefix = dest;
 183                 eigrp_fsm_event(&msg);
 184
 185                 eigrp_IPv4_InternalTLV_free(tlv);
 186         }
 187         eigrp_hello_send_ack(nbr);
 188 }