El procesamiento de mensajes tiene este esquema general:
- Recibir mensajes entrantes de ruta.
- Actualizar tablas de rutas según corresponda.
- Responder según sea necesario, a menudo regenerando el mensaje entrante con información actualizada.
Después de procesar un mensaje, la información se almacena en la tabla de rutas. Por este motivo es apropiado establecer valores en los campos de mensajes salientes, utilizando la información de la tabla de rutas o los campos del mensaje entrante.
/* This pseudocode shows possible RFC 5444 actions, and would not
be performed by the AODVv2 implementation. It is shown only to
provide more understanding about the AODVv2 message that will be
constructed by RFC 5444.
MAL = Message Address Length
MF = Message Flags
Size = number of octets in MsgHdr, AddrBlk, AddrTLVs */
build_rfc_5444_message_header (msgType, Flags, AddrFamily, Size, hopLimit, hopCount, tlvLength)
{
/* Build RFC 5444 message header fields */
msg-type = msgType;
MF = Flags;
MAL = 3 or 15; // for IPv4 or IPv6
msg-size = Size;
msg-hop-limit = hopLimit;
/* if hopCount is 0, do not include */
if (hopCount != 0)
msg-hop-count = hopCount;
msg.tlvs-length = tlvLength;
}/* Process a RREQ received on link L */
receive_RREQ (inRREQ, L)
{
if (inRREQ.NbrIP present in blacklist)
{
if (blacklist_expiration_time < CurrentTime)
return; // don't process or regenerate RREQ
else
remove nbrIP from blacklist;
}
if (inRREQ does not contain msg_hop_limit, OrigAddr,
TargAddr, OrigSeqNum, OrigMetric)
return;
if (msg_hop_count > MAX_HOPCOUNT)
return;
if (msg_hop_limit < 0)
return;
if (inRREQ.OrigAddr and inRREQ.TargAddr are not valid routable
and unicast addresses)
return;
if (inRREQ.MetricType is present but an unknown value)
return;
if (inRREQ.OrigMetric > MAX_METRIC[inRREQ.MetricType] - Cost(L))
return;
/* Extract inRREQ values */
advRte.Address = inRREQ.OrigAddr;
advRte.PrefixLength = inRREQ.OrigPrefixLen; (if present)
or the address length of advRte.Address;
advRte.SeqNum = inRREQ.OrigSeqNum;
advRte.MetricType = inRREQ.MetricType;
advRte.Metric = inRREQ.OrigMetric;
advRte.Cost = inRREQ.OrigMetric + Cost(L);
//according to the indicated MetricType
advRte.ValidityTime = inRREQ.ValidityTime; //if present
advRte.NextHopIP = inRREQ.NbrIP;
advRte.NextHopIntf = inRREQ.Netif;
advRte.HopCount = inRREQ.HopCount;
advRte.HopLimit = inRREQ.HopLimit;
rte = process_routing_info (advRte);
/* Update the RteMsgTable and determine if the RREQ needs
to be regenerated */
regenerate = Update_Rte_Msg_Table(inRREQ);
if (inRREQ.TargAddr is in Router Client list)
generate_RREP(inRREQ, rte);
else if (regenerate)
regenerate_RREQ(inRREQ, rte);
}
/* Generate a route request message to find a route from OrigAddr
to TargAddr using the given MetricType
origAddr = IP address of Router Client which generated the
packet to be forwarded
origPrefix = prefix length associated with the Router Client
targAddr = destination IP address in the packet to be forwarded
targSeqNum = sequence number in existing route to targAddr
mType = metric type for the requested route */
generate_RREQ(origAddr, origPrefix, targAddr, targSeqNum, mType)
{
/* Increment sequence number in nonvolatile storage */
mySeqNum = (1 + mySeqNum);
/* Marshall parameters */
outRREQ.HopLimit = MAX_HOPCOUNT;
outRREQ.HopCount = 0; // if included
outRREQ.MetricType = mType; //include if not DEFAULT_METRIC_TYPE
outRREQ.OrigAddr = origAddr;
outRREQ.TargAddr = targAddr;
outRREQ.OrigPrefixLen = origPrefix; //include if not address length
outRREQ.OrigSeqNum = mySeqNum;
outRREQ.TargSeqNum = targSeqNum; //included if available
outRREQ.OrigMetric = Route[OrigAddr].Metric; //zero by default
outRREQ.ValidityTime = limit for route to OrigAddr; //if required
/* Build Address Blk using prefix length information from
outRREQ.OrigPrefixLen if necessary */
AddrBlk = {outRREQ.OrigAddr, outRREQ.TargAddr};
/* Include sequence numbers in appropriate Address Block TLVs */
/* OrigSeqNum Address Block TLV */
origSeqNumAddrBlkTlv.value = outRREQ.OrigSeqNum;
/* TargSeqNum Address Block TLV */
if (outRREQ.TargSeqNum is known)
targSeqNumAddrBlkTlv.value = outRREQ.TargSeqNum;
/* Build Metric Address Block TLV, include Metric AddrBlkTlv
Extension type if a non-default metric */
metricAddrBlkTlv.value = outRREQ.OrigMetric;
if (outRREQ.MetricType != DEFAULT_METRIC_TYPE)
metricAddrBlkTlv.typeExtension = outRREQ.MetricType;
if (outRREQ.ValidityTime is required)
{
/* Build VALIDITY_TIME Address Block TLV */
VALIDITY_TIMEAddrBlkTlv.value = outRREQ.ValidityTime;
}
build_rfc_5444_message_header (RREQ, 4, IPv6, NN,
outRREQ.HopLimit, outRREQ.HopCount, tlvLength);
/* multicast RFC 5444 message to LL-MANET-Routers */
}
/* Called from receive_RREQ()
rte = the route to OrigAddr */
regenerate_RREQ (inRREQ, rte)
{
outRREQ.HopLimit = inRREQ.HopLimit - 1;
if (outRREQ.HopLimit == 0)
return; // don't regenerate
if (inRREQ.HopCount exists)
{
if (inRREQ.HopCount >= MAX_HOPCOUNT)
return; // don't regenerate
outRREQ.HopCount = inRREQ.HopCount + 1;
}
/* Marshall parameters */
outRREQ.MetricType = rte.MetricType;
outRREQ.OrigAddr = rte.Address;
outRREQ.TargAddr = inRREQ.TargAddr;
/* include prefix length if not equal to address length */
outRREQ.OrigPrefixLen = rte.PrefixLength;
outRREQ.OrigSeqNum = rte.SeqNum;
outRREQ.TargSeqNum = inRREQ.TargSeqNum; // if present
outRREQ.OrigMetric = rte.Metric;
outRREQ.ValidityTime = rte.ValidityTime;
or the time limit this router wishes to put on
route to OrigAddr
/* Build Address Block using prefix length information from
outRREQ.OrigPrefixLen if necessary */
AddrBlk = {outRREQ.OrigAddr, outRREQ.TargAddr};
/* Include sequence numbers in appropriate Address Block TLVs */
/* OrigSeqNum Address Block TLV */
origSeqNumAddrBlkTlv.value = outRREQ.OrigSeqNum;
/* TargSeqNum Address Block TLV */
if (outRREQ.TargSeqNum is known)
targSeqNumAddrBlkTlv.value = outRREQ.TargSeqNum;
/* Build Metric Address Block TLV, include Metric AddrBlkTlv
Extension type if a non-default metric */
metricAddrBlkTlv.value = outRREQ.OrigMetric;
if (outRREQ.MetricType != DEFAULT_METRIC_TYPE)
metricAddrBlkTlv.typeExtension = outRREQ.MetricType;
if (outRREQ.ValidityTime is required)
{
/* Build VALIDITY_TIME Address Block TLV */
VALIDITY_TIMEAddrBlkTlv.value = outRREQ.ValidityTime;
}
build_rfc_5444_message_header (RREQ, 4, IPv4 or IPv6, NN,
outRREQ.HopLimit, outRREQ.HopCount, tlvLength);
/* Multicast RFC 5444 message to LL-MANET-Routers, or if
inRREQ was unicast, the message can be unicast to the next
hop on the route to TargAddr, if known */
}generate_rrep(inRREQ, rte)
{
/* Increment sequence number in nonvolatile storage */
mySeqNum = (1 + mySeqNum);
/* Marshall parameters */
outRREP.HopLimit = inRREQ.HopCount;
outRREP.HopCount = 0;
/* Include the AckReq when:
- previous RREP does not seem to enable any data flow, OR
- when RREQ is received from same OrigAddr after RREP was
unicast to rte.NextHop */
outRREP.AckReq = TRUE or FALSE; //TRUE if acknowledgement required
/* if included, set timeout RREP_Ack_SENT_TIMEOUT */
if (rte.MetricType != DEFAULT_METRIC_TYPE)
outRREP.MetricType = rte.MetricType;
outRREP.OrigAddr = inRREQ.Address;
outRREP.TargAddr = rte.TargAddr;
outRREP.TargPrefixLen = rte.PrefixLength; //if not address length
outRREP.TargSeqNum = mySeqNum;
outRREP.TargMetric = rte.Metric;
outRREP.ValidityTime = limit for route to TargAddr; //if required
if (outRREP.AckReq == TRUE)
/* include AckReq Message TLV */
/* Build Address Block using prefix length information from
outRREP.TargPrefixLen if necessary */
AddrBlk = {outRREP.OrigAddr, outRREP.TargAddr};
/* TargSeqNum Address Block TLV */
targSeqNumAddrBlkTlv.value = outRREP.TargSeqNum;
/* Build Metric Address Block TLV include Metric AddrBlkTlv
Extension type if a non-default metric */
metricAddrBlkTlv.value = outRREP.TargMetric;
if (outRREP.MetricType != DEFAULT_METRIC_TYPE)
metricAddrBlkTlv.typeExtension = outRREP.MetricType;
if (outRREP.ValidityTime is required)
{
/* Build VALIDITY_TIME Address Block TLV */
VALIDITY_TIMEAddrBlkTlv.value = outRREP.ValidityTime;
}
Build_RFC_5444_Message_Header (RREP, 4, IPv4 or IPv6, NN,
outRREP.HopLimit, outRREQ.HopCount, tlvLength);
/* unicast RFC 5444 message to rte[OrigAddr].NextHop */
}/* Process a RREP received on link L */
Receive_RREP (inRREP, L)
{
if (inRREP.NbrIP present in blacklist)
{
if (blacklist_expiration_time < CurrentTime)
return; // don't process or regenerate RREP
else
remove NbrIP from blacklist;
}
if (inRREP does not contain msg_hop_limit, OrigAddr,
TargAddr, TargSeqNum, TargMetric)
return;
if (msg_hop_count > MAX_HOPCOUNT)
return;
if (msg_hop_limit < 0)
return;
if (inRREP.OrigAddr and inRREQ.TargAddr are not
valid routable and unicast addresses)
return;
if (inRREP.MetricType is present but an unknown value)
return;
if (inRREP.TargMetric > MAX_METRIC[inRREP.MetricType])
return;
/* Extract inRREP values */
advRte.Address = inRREP.TargAddr;
advRte.PrefixLength = inRREP.TargPrefixLen; //if present
or the address length of advRte.Address;
advRte.SeqNum = inRREP.TargSeqNum;
advRte.MetricType = inRREP.MetricType;
advRte.Metric = inRREP.TargMetric;
advRte.Cost = inRREP.TargMetric + Cost(L);
//according to the indicated MetricType
advRte.ValidityTime = inRREP.ValidityTime; //if present
advRte.NextHopIP = inRREP.NbrIP;
advRte.NextHopIntf = inRREP.Netif;
advRte.HopCount = inRREP.HopCount;
advRte.HopLimit = inRREP.HopLimit; //if included
rte = Process_Routing_Info (advRte);
` if (inRREP includes AckReq data element)
Generate_RREP_Ack(inRREP);
/* Update the RteMsgTable and determine if the RREP needs
to be regenerated */
regenerate = Update_Rte_Msg_Table(inRREP);
if (inRREP.TargAddr is in the Router Client list)
send_buffered_packets(rte); /* start to use the route */
else if (regenerate)
Regenerate_RREP(inRREP, rte);
}Regenerate_RREP(inRREP, rte)
{
if (rte does not exist)
{
Generate_RERR(inRREP);
return;
}
outRREP.HopLimit = inRREP.HopLimit - 1;
if (outRREP.HopLimit == 0) /* don't regenerate */
return;
if (inRREP.HopCount exists)
{
if (inRREP.HopCount >= MAX_HOPCOUNT)
return; // don't regenerate the RREP
outRREP.HopCount = inRREP.HopCount + 1;
}
/* Marshall parameters */
/* Include the AckReq when:
- previous unicast RREP seems not to enable data flow, OR
- when RREQ is received from same OrigAddr after RREP
was unicast to rte.NextHop */
outRREP.AckReq = TRUE or FALSE; //TRUE if acknowledgement required
/* if included, set timeout RREP_Ack_SENT_TIMEOUT */
if (rte.MetricType != DEFAULT_METRIC_TYPE)
outRREP.MetricType = rte.MetricType;
outRREP.OrigAddr = inRREP.OrigAddr;
outRREP.TargAddr = rte.Address;
outRREP.TargPrefixLen = rte.PrefixLength; //if not address length
outRREP.TargSeqNum = rte.SeqNum;
outRREP.TargMetric = rte.Metric;
outRREP.ValidityTime = limit for route to TargAddr; //if required
outRREP.NextHop = rte.NextHop
if (outRREP.AckReq == TRUE)
/* include AckReq Message TLV */
/* Build Address Block using prefix length information from
outRREP.TargPrefixLen if necessary */
AddrBlk = {outRREP.OrigAddr, outRREP.TargAddr};
/* TargSeqNum Address Block TLV */
targSeqNumAddrBlkTlv.value = outRREP.TargSeqNum;
/* Build Metric Address Block TLV include Metric AddrBlkTlv
Extension type if a non-default metric */
metricAddrBlkTlv.value = outRREP.TargMetric;
if (outRREP.MetricType != DEFAULT_METRIC_TYPE)
metricAddrBlkTlv.typeExtension = outRREP.MetricType;
if (outRREP.ValidityTime is required)
{
/* Build VALIDITY_TIME Address Block TLV */
VALIDITY_TIMEAddrBlkTlv.value = outRREP.ValidityTime;
}
Build_RFC_5444_Message_Header (RREP, 4, IPv4 or IPv6, NN,
outRREP.HopLimit, 0, tlvLength);
/* unicast RFC 5444 message to rte[OrigAddr].NextHop */
}