/* $Id$ */
/*
- * Copyright (c) 2006 Stanford University.
+ * Copyright (c) 2008 Stanford University.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* packet. This approach assumes that the network is operating at low
* utilization; its goal is to prevent correlated traffic -- such as
* nodes along a route forwarding packets -- from interfering with itself.
+ * The values for these constants are defined in CC2420ForwardingEngine.h.
+ * A waiting interval is Base wait plus a random wait in the range of
+ * 0 - Wait window.
*
* <table>
* <tr>
* <td><b>Case</b></td>
- * <td><b>CC2420 Wait (ms)</b></td>
- * <td><b>Other Wait (ms)</b></td>
+ * <td><b>Base wait</b></td>
+ * <td><b>Wait window</b></td>
* <td><b>Description</b></td>
* </tr>
* <tr>
* </tr>
* <tr>
* <td>Success</td>
- * <td>16-31</td>
- * <td>128-255</td>
+ * <td>SENDDONE_OK_OFFSET</td>
+ * <td>SENDDONE_OK_WINDOW</td>
* <td>When the ForwardingEngine successfully sends a packet to the next
* hop, it waits this long before sending the next packet in the queue.
* </td>
* </tr>
* <tr>
* <td>Ack Failure</td>
- * <td>8-15</td>
- * <td>128-255</td>
+ * <td>SENDDONE_NOACK_OFFSET</td>
+ * <td>SENDDONE_NOACK_WINDOW</td>
* <td>If the link layer supports acks and the ForwardingEngine did not
* receive an acknowledgment from the next hop, it waits this long before
* trying a retransmission. If the packet has exceeded the retransmission
* </tr>
* <tr>
* <td>Loop Detection</td>
- * <td>32-63</td>
- * <td>512-1023</td>
+ * <td>LOOPY_OFFSET</td>
+ * <td>LOOPY_WINDOW</td>
* <td>If the ForwardingEngine is asked to forward a packet from a node that
* believes it is closer to the root, the ForwardingEngine pauses its
* transmissions for this interval and triggers the RoutingEngine to
* </tr>
* </table>
*
- * <p>The times above are all for CC2420-based platforms. The timings for
- * other platforms depend on their bit rates, as they are based on packet
- * transmission times.</p>
+ * <p>For CC2420-based platforms, SENDDONE_OK_OFFSET and SENDDONE_NOACK_OFFSET are 16ms,
+ LOOPY_OFFSET is 64ms, SENDDONE_OK_WINDOW and SENDDONE_NOACK_WINDOW are 15ms and
+ LOOPY_WINDOW is 63ms. DIfferent radios have different packet timings and so use
+ different constants.</p>
* @author Philip Levis
* @author Kyle Jamieson
// Counts down from the last time we heard from our parent; used
// to expire local state about parent congestion.
- interface Timer<TMilli> as CongestionTimer;
-
interface Cache<message_t*> as SentCache;
interface CtpInfo;
interface PacketAcknowledgements;
* masked by the given mask and added to the given offset.
*/
static void startRetxmitTimer(uint16_t mask, uint16_t offset);
- static void startCongestionTimer(uint16_t mask, uint16_t offset);
/* Indicates whether our client is congested */
bool clientCongested = FALSE;
bool ackPending = FALSE;
/* Keeps track of whether the packet on the head of the queue
- * is being used, and control access to the data-link layer.*/
+ * is being used, and control access to the data-link layer. Note
+ * that CTP may be busy sending but there might be no transmission
+ * scheduled to the link layer, because CTP is using its own layer 3
+ * timers to prevent self-interference.*/
bool sending = FALSE;
/* Keep track of the last parent address we sent to, so that
}
}
}
-
+
+ static void startRetxmitTimer(uint16_t mask, uint16_t offset) {
+ uint16_t r = call Random.rand16();
+ r &= mask;
+ r += offset;
+ call RetxmitTimer.startOneShot(r);
+ dbg("Forwarder", "Rexmit timer will fire in %hu ms\n", r);
+ }
+
/*
* If the ForwardingEngine has stopped sending packets because
* these has been no route, then as soon as one is found, start
* already sending packets (the RetxmitTimer isn't running), post
* sendTask. It could be that the engine is running and sendTask
* has already been posted, but the post-once semantics make this
- * not matter.
+ * not matter. What's important is that you don't post sendTask
+ * if the retransmit timer is running; this would circumvent the
+ * timer and send a packet before it fires.
*/
command error_t Send.send[uint8_t client](message_t* msg, uint8_t len) {
ctp_data_header_t* hdr;
* These is where all of the send logic is. When the ForwardingEngine
* wants to send a packet, it posts this task. The send logic is
* independent of whether it is a forwarded packet or a packet from
- * a send client.
+ * a send clientL the two cases differ in how memory is managed in
+ * sendDone.
*
* The task first checks that there is a packet to send and that
* there is a valid route. It then marshals the relevant arguments
task void sendTask() {
dbg("Forwarder", "%s: Trying to send a packet. Queue size is %hhu.\n", __FUNCTION__, call SendQueue.size());
if (sending) {
- dbg("Forwarder", "%s: busy, don't send\n", __FUNCTION__);
+ dbg("Forwarder", "%s: busy, don't send.\n", __FUNCTION__);
call CollectionDebug.logEvent(NET_C_FE_SEND_BUSY);
return;
}
else if (call SendQueue.empty()) {
- dbg("Forwarder", "%s: queue empty, don't send\n", __FUNCTION__);
+ dbg("Forwarder", "%s: queue empty, nothing to send.\n", __FUNCTION__);
call CollectionDebug.logEvent(NET_C_FE_SENDQUEUE_EMPTY);
return;
}
else if (!call RootControl.isRoot() &&
!call UnicastNameFreeRouting.hasRoute()) {
- dbg("Forwarder", "%s: no route, don't send, start retry timer\n", __FUNCTION__);
- call RetxmitTimer.startOneShot(10000);
-
- // send a debug message to the uart
+ // Technically, this retry isn't necessary, as if a route
+ // is found we'll get an event. But just in case such an event
+ // is lost (e.g., a bug in the routing engine), we retry.
+ // Otherwise the forwarder might hang indefinitely. As this test
+ // doesn't require radio activity, the energy cost is minimal.
+ dbg("Forwarder", "%s: no route, don't send, try again in %i.\n", __FUNCTION__, NO_ROUTE_RETRY);
+ call RetxmitTimer.startOneShot(NO_ROUTE_RETRY);
call CollectionDebug.logEvent(NET_C_FE_NO_ROUTE);
-
return;
}
- /*
- else if (parentCongested) {
- // Do nothing; the congestion timer is necessarily set which
- // will clear parentCongested and repost sendTask().
- dbg("Forwarder", "%s: sendTask deferring for congested parent\n",
- __FUNCTION__);
- call CollectionDebug.logEvent(NET_C_FE_CONGESTION_SENDWAIT);
- }
- */
else {
+ // We can send a packet.
error_t subsendResult;
fe_queue_entry_t* qe = call SendQueue.head();
uint8_t payloadLen = call SubPacket.payloadLength(qe->msg);
am_addr_t dest = call UnicastNameFreeRouting.nextHop();
uint16_t gradient;
- if (call CtpInfo.isNeighborCongested(dest)) {
- // Our parent is congested. We should wait.
- // Don't repost the task, CongestionTimer will do the job
- if (! parentCongested ) {
- parentCongested = TRUE;
- call CollectionDebug.logEvent(NET_C_FE_CONGESTION_BEGIN);
- }
- if (! call CongestionTimer.isRunning()) {
- startCongestionTimer(CONGESTED_WAIT_WINDOW, CONGESTED_WAIT_OFFSET);
- }
- dbg("Forwarder", "%s: sendTask deferring for congested parent\n",
- __FUNCTION__);
- //call CollectionDebug.logEvent(NET_C_FE_CONGESTION_SENDWAIT);
- return;
- }
- if (parentCongested) {
- parentCongested = FALSE;
- call CollectionDebug.logEvent(NET_C_FE_CONGESTION_END);
- }
- // Now we check if we have already sent a packet with matching signature
+ // Make sure we haven't sent this packet before with the same THL.
+ // Note that this implies it's a forwarded packet, so we can
+ // circumvent the client or forwarded branch for freeing
+ // the buffer.
if (call SentCache.lookup(qe->msg)) {
call CollectionDebug.logEvent(NET_C_FE_DUPLICATE_CACHE_AT_SEND);
call SendQueue.dequeue();
/* If our current parent is not the same as the last parent
we sent do, then reset the count of unacked packets: don't
penalize a new parent for the failures of a prior one.*/
+ // Give the high retry count, keeping this seems like a bad idea.
+ // If you've reached MAX_RETRIES, you've cycled through a bunch of
+ // parents. -pal
+ /*
if (dest != lastParent) {
qe->retries = MAX_RETRIES;
lastParent = dest;
}
-
+ */
+
+ // We've decided we're going to send.
dbg("Forwarder", "Sending queue entry %p\n", qe);
+ // If we're a root, copy the packet to a receive buffer and signal
+ // receive. We have to copy because send expects the buffer back,
+ // but receive might do a buffer swap.
if (call RootControl.isRoot()) {
collection_id_t collectid = getHeader(qe->msg)->type;
memcpy(loopbackMsgPtr, qe->msg, sizeof(message_t));
ackPending = (call PacketAcknowledgements.requestAck(qe->msg) == SUCCESS);
- // Set or clear the congestion bit on *outgoing* packets.
- if (call CtpCongestion.isCongested())
- call CtpPacket.setOption(qe->msg, CTP_OPT_ECN);
- else
- call CtpPacket.clearOption(qe->msg, CTP_OPT_ECN);
+ // Make sure the ECN bit is not set.
+ call CtpPacket.clearOption(qe->msg, CTP_OPT_ECN);
subsendResult = call SubSend.send(dest, qe->msg, payloadLen);
if (subsendResult == SUCCESS) {
sending = TRUE;
dbg("Forwarder", "%s: subsend succeeded with %p.\n", __FUNCTION__, qe->msg);
if (qe->client < CLIENT_COUNT) {
- dbg("Forwarder", "%s: client packet.\n", __FUNCTION__);
+ dbg("Forwarder", "%s: client packet.\n", __FUNCTION__);
}
else {
- dbg("Forwarder", "%s: forwarded packet.\n", __FUNCTION__);
+ dbg("Forwarder", "%s: forwarded packet.\n", __FUNCTION__);
}
return;
}
// This shouldn't happen, as we sit on top of a client and
// control our own output; it means we're trying to
// double-send (bug). This means we expect a sendDone, so just
- // wait for that: when the sendDone comes in, // we'll try
+ // wait for that: when the sendDone comes in, we'll try
// sending this packet again.
dbg("Forwarder", "%s: subsend failed from EBUSY.\n", __FUNCTION__);
// send a debug message to the uart
call CollectionDebug.logEvent(NET_C_FE_SUBSEND_BUSY);
}
+ // The packet is too big: truncate it and retry.
else if (subsendResult == ESIZE) {
dbg("Forwarder", "%s: subsend failed from ESIZE: truncate packet.\n", __FUNCTION__);
call Packet.setPayloadLength(qe->msg, call Packet.maxPayloadLength());
// Immediate retransmission is the worst thing to do.
dbg("Forwarder", "%s: send failed\n", __FUNCTION__);
call CollectionDebug.logEventMsg(NET_C_FE_SENDDONE_FAIL,
- call CollectionPacket.getSequenceNumber(msg),
- call CollectionPacket.getOrigin(msg),
- call AMPacket.destination(msg));
+ call CollectionPacket.getSequenceNumber(msg),
+ call CollectionPacket.getOrigin(msg),
+ call AMPacket.destination(msg));
startRetxmitTimer(SENDDONE_FAIL_WINDOW, SENDDONE_FAIL_OFFSET);
}
else if (ackPending && !call PacketAcknowledgements.wasAcked(msg)) {
call AMPacket.destination(msg));
startRetxmitTimer(SENDDONE_NOACK_WINDOW, SENDDONE_NOACK_OFFSET);
} else {
- //max retries, dropping packet
- if (qe->client < CLIENT_COUNT) {
- clientPtrs[qe->client] = qe;
- signal Send.sendDone[qe->client](msg, FAIL);
- call CollectionDebug.logEventMsg(NET_C_FE_SENDDONE_FAIL_ACK_SEND,
- call CollectionPacket.getSequenceNumber(msg),
- call CollectionPacket.getOrigin(msg),
- call AMPacket.destination(msg));
- } else {
- if (call MessagePool.put(qe->msg) != SUCCESS)
- call CollectionDebug.logEvent(NET_C_FE_PUT_MSGPOOL_ERR);
- if (call QEntryPool.put(qe) != SUCCESS)
- call CollectionDebug.logEvent(NET_C_FE_PUT_QEPOOL_ERR);
- call CollectionDebug.logEventMsg(NET_C_FE_SENDDONE_FAIL_ACK_FWD,
- call CollectionPacket.getSequenceNumber(msg),
- call CollectionPacket.getOrigin(msg),
- call AMPacket.destination(msg));
+ // <Max retries reached, dropping packet: first case is a client packet,
+ // second case is a forwarded packet. Memory management for the
+ // two is different.
+ if (qe->client < CLIENT_COUNT) { // Client packet
+ clientPtrs[qe->client] = qe;
+ signal Send.sendDone[qe->client](msg, FAIL);
+ call CollectionDebug.logEventMsg(NET_C_FE_SENDDONE_FAIL_ACK_SEND,
+ call CollectionPacket.getSequenceNumber(msg),
+ call CollectionPacket.getOrigin(msg),
+ call AMPacket.destination(msg));
+ } else { // Forwarded packet
+ if (call MessagePool.put(qe->msg) != SUCCESS)
+ call CollectionDebug.logEvent(NET_C_FE_PUT_MSGPOOL_ERR);
+ if (call QEntryPool.put(qe) != SUCCESS)
+ call CollectionDebug.logEvent(NET_C_FE_PUT_QEPOOL_ERR);
+ call CollectionDebug.logEventMsg(NET_C_FE_SENDDONE_FAIL_ACK_FWD,
+ call CollectionPacket.getSequenceNumber(msg),
+ call CollectionPacket.getOrigin(msg),
+ call AMPacket.destination(msg));
}
call SendQueue.dequeue();
sending = FALSE;
post sendTask();
}
- event void CongestionTimer.fired() {
- //parentCongested = FALSE;
- //call CollectionDebug.logEventSimple(NET_C_FE_CONGESTION_END, 0);
- post sendTask();
- }
-
-
command bool CtpCongestion.isCongested() {
- // A simple predicate for now to determine congestion state of
- // this node.
- bool congested = (call SendQueue.size() > congestionThreshold) ?
- TRUE : FALSE;
- return ((congested || clientCongested)?TRUE:FALSE);
+ return FALSE;
}
command void CtpCongestion.setClientCongested(bool congested) {
- bool wasCongested = call CtpCongestion.isCongested();
- clientCongested = congested;
- if (!wasCongested && congested) {
- call CtpInfo.triggerImmediateRouteUpdate();
- } else if (wasCongested && ! (call CtpCongestion.isCongested())) {
- call CtpInfo.triggerRouteUpdate();
- }
+ // Do not respond to congestion.
}
+
+ /* signalled when this neighbor is evicted from the neighbor table */
+ event void LinkEstimator.evicted(am_addr_t neighbor) {}
+
+ // Packet ADT commands
command void Packet.clear(message_t* msg) {
call SubPacket.clear(msg);
}
-
+
command uint8_t Packet.payloadLength(message_t* msg) {
return call SubPacket.payloadLength(msg) - sizeof(ctp_data_header_t);
}
return payload;
}
+ // CollectionPacket ADT commands
command am_addr_t CollectionPacket.getOrigin(message_t* msg) {return getHeader(msg)->origin;}
-
command collection_id_t CollectionPacket.getType(message_t* msg) {return getHeader(msg)->type;}
command uint8_t CollectionPacket.getSequenceNumber(message_t* msg) {return getHeader(msg)->originSeqNo;}
command void CollectionPacket.setOrigin(message_t* msg, am_addr_t addr) {getHeader(msg)->origin = addr;}
command void CollectionPacket.setType(message_t* msg, collection_id_t id) {getHeader(msg)->type = id;}
command void CollectionPacket.setSequenceNumber(message_t* msg, uint8_t _seqno) {getHeader(msg)->originSeqNo = _seqno;}
-
- //command ctp_options_t CtpPacket.getOptions(message_t* msg) {return getHeader(msg)->options;}
+ // CtpPacket ADT commands
command uint8_t CtpPacket.getType(message_t* msg) {return getHeader(msg)->type;}
command am_addr_t CtpPacket.getOrigin(message_t* msg) {return getHeader(msg)->origin;}
command uint16_t CtpPacket.getEtx(message_t* msg) {return getHeader(msg)->etx;}
command uint8_t CtpPacket.getSequenceNumber(message_t* msg) {return getHeader(msg)->originSeqNo;}
command uint8_t CtpPacket.getThl(message_t* msg) {return getHeader(msg)->thl;}
-
command void CtpPacket.setThl(message_t* msg, uint8_t thl) {getHeader(msg)->thl = thl;}
command void CtpPacket.setOrigin(message_t* msg, am_addr_t addr) {getHeader(msg)->origin = addr;}
command void CtpPacket.setType(message_t* msg, uint8_t id) {getHeader(msg)->type = id;}
-
+ command void CtpPacket.setEtx(message_t* msg, uint16_t e) {getHeader(msg)->etx = e;}
+ command void CtpPacket.setSequenceNumber(message_t* msg, uint8_t _seqno) {getHeader(msg)->originSeqNo = _seqno;}
command bool CtpPacket.option(message_t* msg, ctp_options_t opt) {
return ((getHeader(msg)->options & opt) == opt) ? TRUE : FALSE;
}
-
command void CtpPacket.setOption(message_t* msg, ctp_options_t opt) {
getHeader(msg)->options |= opt;
}
-
command void CtpPacket.clearOption(message_t* msg, ctp_options_t opt) {
getHeader(msg)->options &= ~opt;
}
- command void CtpPacket.setEtx(message_t* msg, uint16_t e) {getHeader(msg)->etx = e;}
- command void CtpPacket.setSequenceNumber(message_t* msg, uint8_t _seqno) {getHeader(msg)->originSeqNo = _seqno;}
// A CTP packet ID is based on the origin and the THL field, to
// implement duplicate suppression as described in TEP 123.
-
command bool CtpPacket.matchInstance(message_t* m1, message_t* m2) {
return (call CtpPacket.getOrigin(m1) == call CtpPacket.getOrigin(m2) &&
call CtpPacket.getSequenceNumber(m1) == call CtpPacket.getSequenceNumber(m2) &&
call CtpPacket.getType(m1) == call CtpPacket.getType(m2));
}
+
+ /******** Defaults. **************/
+
default event void
Send.sendDone[uint8_t client](message_t *msg, error_t error) {
}
default command collection_id_t CollectionId.fetch[uint8_t client]() {
return 0;
}
-
- static void startRetxmitTimer(uint16_t mask, uint16_t offset) {
- uint16_t r = call Random.rand16();
- r &= mask;
- r += offset;
- call RetxmitTimer.startOneShot(r);
- dbg("Forwarder", "Rexmit timer will fire in %hu ms\n", r);
- }
-
- static void startCongestionTimer(uint16_t mask, uint16_t offset) {
- uint16_t r = call Random.rand16();
- r &= mask;
- r += offset;
- call CongestionTimer.startOneShot(r);
- dbg("Forwarder", "Congestion timer will fire in %hu ms\n", r);
- }
-
- /* signalled when this neighbor is evicted from the neighbor table */
- event void LinkEstimator.evicted(am_addr_t neighbor) {
- }
-
-
+
/* Default implementations for CollectionDebug calls.
* These allow CollectionDebug not to be wired to anything if debugging
* is not desired. */
-
- default command error_t CollectionDebug.logEvent(uint8_t type) {
- return SUCCESS;
- }
- default command error_t CollectionDebug.logEventSimple(uint8_t type, uint16_t arg) {
- return SUCCESS;
- }
- default command error_t CollectionDebug.logEventDbg(uint8_t type, uint16_t arg1, uint16_t arg2, uint16_t arg3) {
- return SUCCESS;
- }
- default command error_t CollectionDebug.logEventMsg(uint8_t type, uint16_t msg, am_addr_t origin, am_addr_t node) {
- return SUCCESS;
- }
- default command error_t CollectionDebug.logEventRoute(uint8_t type, am_addr_t parent, uint8_t hopcount, uint16_t metric) {
- return SUCCESS;
- }
+
+ default command error_t CollectionDebug.logEvent(uint8_t type) {
+ return SUCCESS;
+ }
+ default command error_t CollectionDebug.logEventSimple(uint8_t type, uint16_t arg) {
+ return SUCCESS;
+ }
+ default command error_t CollectionDebug.logEventDbg(uint8_t type, uint16_t arg1, uint16_t arg2, uint16_t arg3) {
+ return SUCCESS;
+ }
+ default command error_t CollectionDebug.logEventMsg(uint8_t type, uint16_t msg, am_addr_t origin, am_addr_t node) {
+ return SUCCESS;
+ }
+ default command error_t CollectionDebug.logEventRoute(uint8_t type, am_addr_t parent, uint8_t hopcount, uint16_t metric) {
+ return SUCCESS;
+ }
}
-/* Rodrigo. This is an alternative
- event void CtpInfo.ParentCongested(bool congested) {
- if (congested) {
- // We've overheard our parent's ECN bit set.
- startCongestionTimer(CONGESTED_WAIT_WINDOW, CONGESTED_WAIT_OFFSET);
- parentCongested = TRUE;
- call CollectionDebug.logEvent(NET_C_FE_CONGESTION_BEGIN);
- } else {
- // We've overheard our parent's ECN bit cleared.
- call CongestionTimer.stop();
- parentCongested = FALSE;
- call CollectionDebug.logEventSimple(NET_C_FE_CONGESTION_END, 1);
- post sendTask();
- }
- }
-*/
-
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