A Discrete-Event Network Simulator
API
tcp-rate-ops.cc
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2018 Natale Patriciello <natale.patriciello@gmail.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation;
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  *
18  */
19 #include "tcp-rate-ops.h"
20 #include "ns3/log.h"
21 #include "ns3/simulator.h"
22 
23 namespace ns3 {
24 
25 NS_LOG_COMPONENT_DEFINE ("TcpRateOps");
26 NS_OBJECT_ENSURE_REGISTERED (TcpRateOps);
27 
28 TypeId
30 {
31  static TypeId tid = TypeId ("ns3::TcpRateOps")
32  .SetParent<Object> ()
33  .SetGroupName ("Internet")
34  ;
35  return tid;
36 }
37 
39 
40 TypeId
42 {
43  static TypeId tid = TypeId ("ns3::TcpRateLinux")
45  .SetGroupName ("Internet")
46  .AddTraceSource ("TcpRateUpdated",
47  "Tcp rate information has been updated",
49  "ns3::TcpRateLinux::TcpRateUpdated")
50  .AddTraceSource ("TcpRateSampleUpdated",
51  "Tcp rate sample has been updated",
53  "ns3::TcpRateLinux::TcpRateSampleUpdated")
54  ;
55  return tid;
56 }
57 
59 TcpRateLinux::GenerateSample (uint32_t delivered, uint32_t lost, bool is_sack_reneg,
60  uint32_t priorInFlight, const Time &minRtt)
61 {
62  NS_LOG_FUNCTION (this << delivered << lost << is_sack_reneg);
63 
64  /* Clear app limited if bubble is acked and gone. */
66  {
67  NS_LOG_INFO ("Updating Rate m_appLimited to zero");
68  m_rate.m_appLimited = 0;
69  }
70 
71  NS_LOG_INFO ("Updating RateSample m_ackedSacked=" << delivered <<
72  ", m_bytesLoss=" << lost << " and m_priorInFlight" << priorInFlight);
73  m_rateSample.m_ackedSacked = delivered; /* freshly ACKed or SACKed */
74  m_rateSample.m_bytesLoss = lost; /* freshly marked lost */
75  m_rateSample.m_priorInFlight = priorInFlight;
76 
77  /* Return an invalid sample if no timing information is available or
78  * in recovery from loss with SACK reneging. Rate samples taken during
79  * a SACK reneging event may overestimate bw by including packets that
80  * were SACKed before the reneg.
81  */
82  if (m_rateSample.m_priorTime == Seconds (0) || is_sack_reneg)
83  {
84  NS_LOG_INFO ("PriorTime is zero, invalidating sample");
88  return m_rateSample;
89  }
90 
91  // LINUX:
92  // /* Model sending data and receiving ACKs as separate pipeline phases
93  // * for a window. Usually the ACK phase is longer, but with ACK
94  // * compression the send phase can be longer. To be safe we use the
95  // * longer phase.
96  // */
97  // auto snd_us = m_rateSample.m_interval; /* send phase */
98  // auto ack_us = Simulator::Now () - m_rateSample.m_prior_mstamp;
99  // m_rateSample.m_interval = std::max (snd_us, ack_us);
100 
103  NS_LOG_INFO ("Updating sample interval=" << m_rateSample.m_interval << " and delivered data" << m_rateSample.m_delivered);
104 
105  /* Normally we expect m_interval >= minRtt.
106  * Note that rate may still be over-estimated when a spuriously
107  * retransmistted skb was first (s)acked because "interval_us"
108  * is under-estimated (up to an RTT). However continuously
109  * measuring the delivery rate during loss recovery is crucial
110  * for connections suffer heavy or prolonged losses.
111  */
112  if (m_rateSample.m_interval < minRtt)
113  {
114  NS_LOG_INFO ("Sampling interval is invalid");
116  m_rateSample.m_priorTime = Seconds (0); // To make rate sample invalid
118  return m_rateSample;
119  }
120 
121  /* Record the last non-app-limited or the highest app-limited bw */
125  {
130  NS_LOG_INFO ("Updating delivery rate=" << m_rateSample.m_deliveryRate);
131  }
132 
134  return m_rateSample;
135 }
136 
137 void
138 TcpRateLinux::CalculateAppLimited (uint32_t cWnd, uint32_t in_flight,
139  uint32_t segmentSize, const SequenceNumber32 &tailSeq,
140  const SequenceNumber32 &nextTx, const uint32_t lostOut,
141  const uint32_t retransOut)
142 {
143  NS_LOG_FUNCTION (this);
144 
145  /* Missing checks from Linux:
146  * - Nothing in sending host's qdisc queues or NIC tx queue. NOT IMPLEMENTED
147  */
148  if (tailSeq - nextTx < static_cast<int32_t> (segmentSize) // We have less than one packet to send.
149  && in_flight < cWnd // We are not limited by CWND.
150  && lostOut <= retransOut) // All lost packets have been retransmitted.
151  {
152  m_rate.m_appLimited = std::max<uint32_t> (m_rate.m_delivered + in_flight, 1);
154  }
155 
156  // m_appLimited will be reset once in GenerateSample, if it has to be.
157  // else
158  // {
159  // m_rate.m_appLimited = 0;
160  // }
161 }
162 
163 void
165 {
166  NS_LOG_FUNCTION (this << skb);
167 
169 
170  if (skbInfo.m_deliveredTime == Time::Max ())
171  {
172  return;
173  }
174 
175  m_rate.m_delivered += skb->GetSeqSize ();
177 
180  {
186 
188 
190  }
191 
192  /* Mark off the skb delivered once it's taken into account to avoid being
193  * used again when it's cumulatively acked, in case it was SACKed.
194  */
195  skbInfo.m_deliveredTime = Time::Max ();
198 }
199 
200 void
201 TcpRateLinux::SkbSent (TcpTxItem *skb, bool isStartOfTransmission)
202 {
203  NS_LOG_FUNCTION (this << skb << isStartOfTransmission);
204 
206 
207  /* In general we need to start delivery rate samples from the
208  * time we received the most recent ACK, to ensure we include
209  * the full time the network needs to deliver all in-flight
210  * packets. If there are no packets in flight yet, then we
211  * know that any ACKs after now indicate that the network was
212  * able to deliver those packets completely in the sampling
213  * interval between now and the next ACK.
214  *
215  * Note that we use the entire window size instead of bytes_in_flight
216  * because the latter is a guess based on RTO and loss-marking
217  * heuristics. We don't want spurious RTOs or loss markings to cause
218  * a spuriously small time interval, causing a spuriously high
219  * bandwidth estimate.
220  */
221  if (isStartOfTransmission)
222  {
223  NS_LOG_INFO ("Starting of a transmission at time " << Simulator::Now ().GetSeconds ());
227  }
228 
231  skbInfo.m_isAppLimited = (m_rate.m_appLimited != 0);
232  skbInfo.m_delivered = m_rate.m_delivered;
233 }
234 
235 std::ostream &
236 operator<< (std::ostream & os, TcpRateLinux::TcpRateConnection const & rate)
237 {
238  os << "m_delivered = " << rate.m_delivered << std::endl;
239  os << "m_deliveredTime = " << rate.m_deliveredTime << std::endl;
240  os << "m_firstSentTime = " << rate.m_firstSentTime << std::endl;
241  os << "m_appLimited = " << rate.m_appLimited << std::endl;
242  os << "m_rateDelivered = " << rate.m_rateDelivered << std::endl;
243  os << "m_rateInterval = " << rate.m_rateInterval << std::endl;
244  os << "m_rateAppLimited = " << rate.m_rateAppLimited << std::endl;
245  os << "m_txItemDelivered = " << rate.m_txItemDelivered << std::endl;
246  return os;
247 }
248 
249 std::ostream &
250 operator<< (std::ostream & os, TcpRateLinux::TcpRateSample const & sample)
251 {
252  os << "m_deliveryRate = " << sample.m_deliveryRate << std::endl;
253  os << " m_isAppLimited = " << sample.m_isAppLimited << std::endl;
254  os << " m_interval = " << sample.m_interval << std::endl;
255  os << " m_delivered = " << sample.m_delivered << std::endl;
256  os << " m_priorDelivered = " << sample.m_priorDelivered << std::endl;
257  os << " m_priorTime = " << sample.m_priorTime << std::endl;
258  os << " m_sendElapsed = " << sample.m_sendElapsed << std::endl;
259  os << " m_ackElapsed = " << sample.m_ackElapsed << std::endl;
260  os << " m_bytesLoss = " << sample.m_bytesLoss << std::endl;
261  os << " m_priorInFlight= " << sample.m_priorInFlight << std::endl;
262  os << " m_ackedSacked = " << sample.m_ackedSacked << std::endl;
263  return os;
264 }
265 
266 bool
267 operator== (TcpRateLinux::TcpRateSample const & lhs, TcpRateLinux::TcpRateSample const & rhs)
268 {
269  return (lhs.m_deliveryRate == rhs.m_deliveryRate
270  && lhs.m_isAppLimited == rhs.m_isAppLimited
271  && lhs.m_interval == rhs.m_interval
272  && lhs.m_delivered == rhs.m_delivered
273  && lhs.m_priorDelivered == rhs.m_priorDelivered
274  && lhs.m_priorTime == rhs.m_priorTime
275  && lhs.m_sendElapsed == rhs.m_sendElapsed
276  && lhs.m_ackElapsed == rhs.m_ackElapsed
277  );
278 }
279 
280 bool
283 {
284  return (lhs.m_delivered == rhs.m_delivered
285  && lhs.m_deliveredTime == rhs.m_deliveredTime
286  && lhs.m_firstSentTime == rhs.m_firstSentTime
287  && lhs.m_appLimited == rhs.m_appLimited
288  );
289 }
290 
291 
292 } // namespace ns3
Simulation virtual time values and global simulation resolution.
Definition: nstime.h:102
#define NS_LOG_FUNCTION(parameters)
If log level LOG_FUNCTION is enabled, this macro will output all input parameters separated by "...
#define NS_OBJECT_ENSURE_REGISTERED(type)
Register an Object subclass with the TypeId system.
Definition: object-base.h:45
Time m_sendElapsed
Send time interval calculated from the most recent packet delivered.
Definition: tcp-rate-ops.h:140
Interface for all operations that involve a Rate monitoring for TCP.
Definition: tcp-rate-ops.h:38
static TypeId GetTypeId(void)
Get the type ID.
Definition: tcp-rate-ops.cc:29
uint32_t m_priorDelivered
The delivered count of the most recent packet delivered.
Definition: tcp-rate-ops.h:138
double GetSeconds(void) const
Get an approximation of the time stored in this instance in the indicated unit.
Definition: nstime.h:361
Time m_ackElapsed
ACK time interval calculated from the most recent packet delivered.
Definition: tcp-rate-ops.h:141
#define NS_LOG_COMPONENT_DEFINE(name)
Define a Log component with a specific name.
Definition: log.h:205
Linux management and generation of Rate information for TCP.
Definition: tcp-rate-ops.h:179
#define NS_LOG_INFO(msg)
Use NS_LOG to output a message of level LOG_INFO.
Definition: log.h:281
uint32_t GetSeqSize(void) const
Get the size in the sequence number space.
Definition: tcp-tx-item.cc:62
uint32_t m_priorInFlight
The value if bytes in flight prior to last received ack.
Definition: tcp-rate-ops.h:143
TracedCallback< const TcpRateSample & > m_rateSampleTrace
Rate Sample trace.
Definition: tcp-rate-ops.h:231
uint32_t m_txItemDelivered
The value of delivered when the acked item was sent.
Definition: tcp-rate-ops.h:167
bool m_isAppLimited
Indicates whether the rate sample is application-limited.
Definition: tcp-rate-ops.h:135
Ptr< const TraceSourceAccessor > MakeTraceSourceAccessor(T a)
Create a TraceSourceAccessor which will control access to the underlying trace source.
TcpRateConnection m_rate
Rate information.
Definition: tcp-rate-ops.h:227
Time m_priorTime
The delivered time of the most recent packet delivered.
Definition: tcp-rate-ops.h:139
TcpRateSample m_rateSample
Rate sample (continuosly updated)
Definition: tcp-rate-ops.h:228
Class for representing data rates.
Definition: data-rate.h:88
static Time Max()
Maximum representable Time.
Definition: nstime.h:279
Item that encloses the application packet and some flags for it.
Definition: tcp-tx-item.h:32
Rate Sample structure.
Definition: tcp-rate-ops.h:132
#define max(a, b)
Definition: 80211b.c:43
uint64_t m_delivered
Connection&#39;s delivered data at the time the packet was sent.
Definition: tcp-tx-item.h:88
int32_t m_delivered
The amount of data marked as delivered over the sampling interval.
Definition: tcp-rate-ops.h:137
bool m_isAppLimited
Connection&#39;s app limited at the time the packet was sent.
Definition: tcp-tx-item.h:91
virtual const TcpRateSample & GenerateSample(uint32_t delivered, uint32_t lost, bool is_sack_reneg, uint32_t priorInFlight, const Time &minRtt) override
Generate a TcpRateSample to feed a congestion avoidance algorithm.
Definition: tcp-rate-ops.cc:59
RateInformation & GetRateInformation(void)
Get (to modify) the Rate Information of this item.
Definition: tcp-tx-item.cc:98
Time m_firstSent
Connection&#39;s first sent time at the time the packet was sent.
Definition: tcp-tx-item.h:90
DataRate m_deliveryRate
The delivery rate sample.
Definition: tcp-rate-ops.h:134
std::ostream & operator<<(std::ostream &os, const Angles &a)
print a struct Angles to output
Definition: angles.cc:42
Various rate-related information, can be accessed by TcpRateOps.
Definition: tcp-tx-item.h:86
Every class exported by the ns3 library is enclosed in the ns3 namespace.
Time m_rateInterval
The value of interval considered to calculate delivery rate.
Definition: tcp-rate-ops.h:169
bool m_rateAppLimited
Was sample was taken when data is app limited?
Definition: tcp-rate-ops.h:170
uint32_t m_ackedSacked
The amount of data acked and sacked in the last received ack.
Definition: tcp-rate-ops.h:144
static Time Now(void)
Return the current simulation virtual time.
Definition: simulator.cc:193
static TypeId GetTypeId(void)
Get the type ID.
Definition: tcp-rate-ops.cc:41
Time m_interval
The length of the sampling interval.
Definition: tcp-rate-ops.h:136
uint32_t m_appLimited
The index of the last transmitted packet marked as application-limited.
Definition: tcp-rate-ops.h:166
Information about the connection rate.
Definition: tcp-rate-ops.h:161
TracedCallback< const TcpRateConnection & > m_rateTrace
Rate trace.
Definition: tcp-rate-ops.h:230
uint64_t m_delivered
The total amount of data in bytes delivered so far.
Definition: tcp-rate-ops.h:163
virtual void CalculateAppLimited(uint32_t cWnd, uint32_t in_flight, uint32_t segmentSize, const SequenceNumber32 &tailSeq, const SequenceNumber32 &nextTx, const uint32_t lostOut, const uint32_t retransOut) override
If a gap is detected between sends, it means we are app-limited.
virtual void SkbSent(TcpTxItem *skb, bool isStartOfTransmission) override
Put the rate information inside the sent skb.
Time m_deliveredTime
Connection&#39;s delivered time at the time the packet was sent.
Definition: tcp-tx-item.h:89
Time Seconds(double value)
Construct a Time in the indicated unit.
Definition: nstime.h:1070
bool operator==(const EventId &a, const EventId &b)
Definition: event-id.h:137
const Time & GetLastSent(void) const
Get a reference to the time the packet was sent for the last time.
Definition: tcp-tx-item.cc:92
Time m_firstSentTime
The send time of the packet that was most recently marked as delivered.
Definition: tcp-rate-ops.h:165
virtual void SkbDelivered(TcpTxItem *skb) override
Update the Rate information after an item is received.
A base class which provides memory management and object aggregation.
Definition: object.h:87
int32_t m_rateDelivered
The amount of data delivered considered to calculate delivery rate.
Definition: tcp-rate-ops.h:168
a unique identifier for an interface.
Definition: type-id.h:58
TypeId SetParent(TypeId tid)
Set the parent TypeId.
Definition: type-id.cc:923
uint32_t m_bytesLoss
The amount of data marked as lost from the most recent ack received.
Definition: tcp-rate-ops.h:142
Time m_deliveredTime
Simulator time when m_delivered was last updated.
Definition: tcp-rate-ops.h:164