eigrpd/eigrp_siareply.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * EIGRP Sending and Receiving EIGRP SIA-Reply Packets.
   4  * Copyright (C) 2013-2014
   5  * Authors:
   6  *   Donnie Savage
   7  *   Jan Janovic
   8  *   Matej Perina
   9  *   Peter Orsag
  10  *   Peter Paluch
  11  */
  12 #include <zebra.h>
  13
  14 #include "thread.h"
  15 #include "memory.h"
  16 #include "linklist.h"
  17 #include "prefix.h"
  18 #include "if.h"
  19 #include "table.h"
  20 #include "sockunion.h"
  21 #include "stream.h"
  22 #include "log.h"
  23 #include "sockopt.h"
  24 #include "checksum.h"
  25 #include "md5.h"
  26 #include "vty.h"
  27
  28 #include "eigrpd/eigrp_structs.h"
  29 #include "eigrpd/eigrpd.h"
  30 #include "eigrpd/eigrp_interface.h"
  31 #include "eigrpd/eigrp_neighbor.h"
  32 #include "eigrpd/eigrp_packet.h"
  33 #include "eigrpd/eigrp_zebra.h"
  34 #include "eigrpd/eigrp_vty.h"
  35 #include "eigrpd/eigrp_dump.h"
  36 #include "eigrpd/eigrp_macros.h"
  37 #include "eigrpd/eigrp_topology.h"
  38 #include "eigrpd/eigrp_fsm.h"
  39
  40 /*EIGRP SIA-REPLY read function*/
  41 void eigrp_siareply_receive(struct eigrp *eigrp, struct ip *iph,
  42                             struct eigrp_header *eigrph, struct stream *s,
  43                             struct eigrp_interface *ei, int size)
  44 {
  45         struct eigrp_neighbor *nbr;
  46         struct TLV_IPv4_Internal_type *tlv;
  47
  48         uint16_t type;
  49
  50         /* increment statistics. */
  51         ei->siaReply_in++;
  52
  53         /* get neighbor struct */
  54         nbr = eigrp_nbr_get(ei, eigrph, iph);
  55
  56         /* neighbor must be valid, eigrp_nbr_get creates if none existed */
  57         assert(nbr);
  58
  59         nbr->recv_sequence_number = ntohl(eigrph->sequence);
  60
  61         while (s->endp > s->getp) {
  62                 type = stream_getw(s);
  63                 if (type == EIGRP_TLV_IPv4_INT) {
  64                         struct prefix dest_addr;
  65
  66                         stream_set_getp(s, s->getp - sizeof(uint16_t));
  67
  68                         tlv = eigrp_read_ipv4_tlv(s);
  69
  70                         dest_addr.family = AFI_IP;
  71                         dest_addr.u.prefix4 = tlv->destination;
  72                         dest_addr.prefixlen = tlv->prefix_length;
  73                         struct eigrp_prefix_descriptor *dest =
  74                                 eigrp_topology_table_lookup_ipv4(
  75                                         eigrp->topology_table, &dest_addr);
  76
  77                         /* If the destination exists (it should, but one never
  78                          * know)*/
  79                         if (dest != NULL) {
  80                                 struct eigrp_fsm_action_message msg;
  81                                 struct eigrp_route_descriptor *entry =
  82                                         eigrp_route_descriptor_lookup(
  83                                                 dest->entries, nbr);
  84                                 msg.packet_type = EIGRP_OPC_SIAQUERY;
  85                                 msg.eigrp = eigrp;
  86                                 msg.data_type = EIGRP_INT;
  87                                 msg.adv_router = nbr;
  88                                 msg.metrics = tlv->metric;
  89                                 msg.entry = entry;
  90                                 msg.prefix = dest;
  91                                 eigrp_fsm_event(&msg);
  92                         }
  93                         eigrp_IPv4_InternalTLV_free(tlv);
  94                 }
  95         }
  96         eigrp_hello_send_ack(nbr);
  97 }
  98
  99 void eigrp_send_siareply(struct eigrp_neighbor *nbr,
 100                          struct eigrp_prefix_descriptor *pe)
 101 {
 102         struct eigrp_packet *ep;
 103         uint16_t length = EIGRP_HEADER_LEN;
 104
 105         ep = eigrp_packet_new(EIGRP_PACKET_MTU(nbr->ei->ifp->mtu), nbr);
 106
 107         /* Prepare EIGRP INIT UPDATE header */
 108         eigrp_packet_header_init(EIGRP_OPC_SIAREPLY, nbr->ei->eigrp, ep->s, 0,
 109                                  nbr->ei->eigrp->sequence_number, 0);
 110
 111         // encode Authentication TLV, if needed
 112         if (nbr->ei->params.auth_type == EIGRP_AUTH_TYPE_MD5
 113             && nbr->ei->params.auth_keychain != NULL) {
 114                 length += eigrp_add_authTLV_MD5_to_stream(ep->s, nbr->ei);
 115         }
 116
 117         length += eigrp_add_internalTLV_to_stream(ep->s, pe);
 118
 119         if ((nbr->ei->params.auth_type == EIGRP_AUTH_TYPE_MD5)
 120             && (nbr->ei->params.auth_keychain != NULL)) {
 121                 eigrp_make_md5_digest(nbr->ei, ep->s, EIGRP_AUTH_UPDATE_FLAG);
 122         }
 123
 124         /* EIGRP Checksum */
 125         eigrp_packet_checksum(nbr->ei, ep->s, length);
 126
 127         ep->length = length;
 128         ep->dst.s_addr = nbr->src.s_addr;
 129
 130         /*This ack number we await from neighbor*/
 131         ep->sequence_number = nbr->ei->eigrp->sequence_number;
 132
 133         if (nbr->state == EIGRP_NEIGHBOR_UP) {
 134                 /*Put packet to retransmission queue*/
 135                 eigrp_fifo_push(nbr->retrans_queue, ep);
 136
 137                 if (nbr->retrans_queue->count == 1) {
 138                         eigrp_send_packet_reliably(nbr);
 139                 }
 140         } else
 141                 eigrp_packet_free(ep);
 142 }