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Session.cpp
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Session.cpp
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/**************************************************************
* Copyright (c) 2010-2013, Dynamic Network Services, Inc.
* Jake Montgomery (jmontgomery@dyn.com) & Tom Daly (tom@dyn.com)
* Distributed under the FreeBSD License - see LICENSE
***************************************************************/
#include "common.h"
#include "Session.h"
#include "utils.h"
#include "Beacon.h"
#include "Scheduler.h"
#include <errno.h>
#include <sys/socket.h>
#include <string.h>
using namespace std;
#ifdef TEST_DROP_FINAL
#warning TEST_DROP_FINAL defined ... testing only!
static int gDropFinalPercent = 60;
#else
static int gDropFinalPercent = 0;
#endif
static const size_t MaxUptimeCount = 4; // number of states to keep track of for logging.
uint32_t Session::m_nextId = 1;
Session::InitialParams::InitialParams() :
detectMulti(3),
desiredMinTx(bfd::BaseMinTxInterval),
requiredMinRx(1000000),
controlPlaneIndependent(false),
adminUpPollWorkaround(true)
{
}
// Note that the inclusion of the Beacon pointer is bad design and sheer
// laziness. This should really be an event sink or callback.
Session::Session(Scheduler &scheduler, Beacon *beacon, uint32_t descriminator, const InitialParams ¶ms) :
m_beacon(beacon),
m_scheduler(&scheduler),
m_remoteAddr(),
m_remoteSourcePort(0),
m_localAddr(),
m_sendPort(0),
m_isActive(false),
m_sessionState(bfd::State::Down),
m_remoteSessionState(bfd::State::Down),
m_localDiscr(descriminator),
m_remoteDiscr(0),
m_localDiag(bfd::Diag::None),
m_desiredMinTxInterval(bfd::BaseMinTxInterval), // Since we start "down" this must be 1s see v10/6.8.3
m_requiredMinRxInterval(params.requiredMinRx),
m_remoteMinRxInterval(1),
m_demandMode(false), // We get to choose this.
m_remoteDemandMode(false),
m_detectMult(params.detectMulti),
m_authType(bfd::AuthType::None), // ??
m_rcvAuthSeq(0),
m_xmitAuthSeq(rand() % UINT32_MAX),
m_authSeqKnown(false),
m_pollState(PollState::None),
m_pollReceived(false),
m_remoteDetectMult(0),
m_remoteDesiredMinTxInterval(0),
m_remoteDiag(bfd::Diag::None),
m_destroyAfterTimeouts(3),
m_remoteDestroyAfterTimeouts(3),
m_timeoutStatus(TimeoutStatus::None),
m_isSuspended(false),
m_immediateControlPacket(false),
m_controlPlaneIndependent(params.controlPlaneIndependent),
m_adminUpPollWorkaround(params.adminUpPollWorkaround),
m_forcedState(false),
m_wantsPollForNewDesiredMinTxInterval(false),
_useDesiredMinTxInterval(bfd::BaseMinTxInterval), // Since we start "down" this must be 1s see v10/6.8.3
m_defaultDesiredMinTxInterval(params.desiredMinTx), // this will not take effect until we are up ... see m_useDesiredMinTxInterva
m_wantsPollForNewRequiredMinRxInterval(false),
_useRequiredMinRxInterval(m_requiredMinRxInterval),
m_receiveTimeoutTimer(this),
m_transmitNextTimer(this)
{
LogAssert(m_scheduler->IsMainThread());
if (m_nextId == 0)
{
// This is unlikely, since we can handle 4 billion sessions.
gLog.LogError("Maximum session count exceeded, refusing new sessions.");
}
else
m_id = m_nextId;
// It may be more efficient to wait until we need these?
char name[32];
snprintf(name, sizeof(name), "<Rcv %u>", m_id);
m_receiveTimeoutTimer = m_scheduler->MakeTimer(name);
snprintf(name, sizeof(name), "<Tx %u>", m_id);
m_transmitNextTimer = m_scheduler->MakeTimer(name);
m_receiveTimeoutTimer->SetCallback(handleReceiveTimeoutTimerCallback, this);
m_receiveTimeoutTimer->SetPriority(Timer::Priority::Low);
m_transmitNextTimer->SetCallback(handletTransmitNextTimerCallback, this);
m_transmitNextTimer->SetPriority(Timer::Priority::Hi);
logSessionTransition();
// Update this only at the end, in case an exception is thrown.
m_nextId++;
}
Session::~Session()
{
LogAssert(m_scheduler->IsMainThread());
}
void Session::deleteTimer(Timer *timer)
{
LogAssert(m_scheduler->IsMainThread());
if (m_scheduler && timer)
{
gLog.Message(Log::Temp, "Free timer %p", timer);
m_scheduler->FreeTimer(timer);
}
}
bool Session::StartPassiveSession(const SockAddr &remoteAddr, const IpAddr &localAddr)
{
LogAssert(m_scheduler->IsMainThread());
// this should only be called once.
LogAssert(!m_remoteAddr.IsValid());
LogAssert(!m_localAddr.IsValid());
if (!LogVerify(remoteAddr.HasPort()))
return false;
if (!LogVerify(!localAddr.IsAny()))
return false;
m_remoteAddr = IpAddr(remoteAddr);
m_remoteSourcePort = remoteAddr.Port();
m_localAddr = localAddr;
m_isActive = false;
return true;
}
bool Session::StartActiveSession(const IpAddr &remoteAddr, const IpAddr &localAddr)
{
LogAssert(m_scheduler->IsMainThread());
// this should only be called once.
if (!LogVerify(!m_remoteAddr.IsValid()))
return false;
if (!LogVerify(!m_localAddr.IsValid()))
return false;
// Any is not valid send address
if (!LogVerify(!localAddr.IsAny()))
return false;
m_remoteAddr = remoteAddr;
m_remoteSourcePort = 0;
m_localAddr = localAddr;
m_isActive = true;
// Start the timers now, and begin sending connection packets.
// We set m_immediateControlPacket because this is a new connection, and there
// is no point in waiting.
m_immediateControlPacket = true;
scheduleTransmit();
return true;
}
bool Session::UpgradeToActiveSession()
{
LogAssert(m_scheduler->IsMainThread());
// Must already have a passive session.
if (!LogVerify(m_remoteAddr.IsValid()))
return false;
if (!LogVerify(m_localAddr.IsValid()))
return false;
if (!LogVerify(!IsActiveSession()))
return false;
m_isActive = true;
// Start the timers now, and begin sending connection packets
scheduleTransmit();
return true;
}
const IpAddr& Session::GetRemoteAddress()
{
LogAssert(m_scheduler->IsMainThread());
return m_remoteAddr;
}
const IpAddr& Session::GetLocalAddress()
{
LogAssert(m_scheduler->IsMainThread());
return m_localAddr;
}
bool Session::IsActiveSession()
{
LogAssert(m_scheduler->IsMainThread());
return m_isActive;
}
// static
bool Session::InitialProcessControlPacket(const uint8_t *data, size_t dataLength, BfdPacket &outPacket)
{
BfdPacketHeader &header = outPacket.header;
if (dataLength < bfd::BasePacketSize)
{
gLog.Optional(Log::Discard, "Discard packet: too small %zu", dataLength);
return false;
}
memcpy(&outPacket, data, min(dataLength, sizeof(outPacket)));
// the early stuff can be checked without worrying about byte order, since they
// are parsed as bytes.
if (header.GetVersion() != 0 && header.GetVersion() != 1)
{
gLog.Optional(Log::Discard, "Discard packet: bad version %hhu", header.GetVersion());
return false;
}
if (header.GetAuth())
{
if (header.length < bfd::BasePacketSize + bfd::AuthHeaderSize)
{
gLog.Optional(Log::Discard, "Discard packet: length too small to include auth %hhu", header.length);
return false;
}
}
else if (header.length < bfd::BasePacketSize)
{
gLog.Optional(Log::Discard, "Discard packet: length too small %hhu", header.length);
return false;
}
else if (header.length > dataLength)
{
gLog.Optional(Log::Discard, "Discard packet: length larger than data %hhu", header.length);
return false;
}
if (header.detectMult == 0)
{
gLog.Optional(Log::Discard, "Discard packet: detectMult is 0.");
return false;
}
if (header.GetMultipoint())
{
gLog.Optional(Log::Discard, "Discard packet: Multipoint bit is set.");
return false;
}
// Can check for 0 without byte order concerns.
if (header.myDisc == 0)
{
gLog.Optional(Log::Discard, "Discard packet: Source Discriminator is 0.");
return false;
}
// Can check for 0 without byte order concerns.
if (header.yourDisc == 0 && header.GetState() != bfd::State::Down && header.GetState() != bfd::State::AdminDown)
{
gLog.Optional(Log::Discard, "Discard packet: No destination discriminator and state is %s.", bfd::StateName(header.GetState()));
return false;
}
// Now we need to worry about byte order
header.myDisc = ntohl(header.myDisc);
header.yourDisc = ntohl(header.yourDisc);
header.txDesiredMinInt = ntohl(header.txDesiredMinInt);
header.rxRequiredMinInt = ntohl(header.rxRequiredMinInt);
header.rxRequiredMinEchoInt = ntohl(header.rxRequiredMinEchoInt);
// packet is good as far as we can tell without a session.
return true;
}
bool Session::ProcessControlPacket(const BfdPacket &packet, in_port_t port)
{
// Assumes that the first few checks have been done.
const BfdPacketHeader &header = packet.header;
uint32_t olduseDesiredMinTxInterval = getUseDesiredMinTxInterval();
uint32_t oldRemoteMinRxInterval = m_remoteMinRxInterval;
LogAssert(m_scheduler->IsMainThread());
logPacketContents(packet, false, true, m_remoteAddr, port, m_localAddr, 0);
if (gDropFinalPercent != 0)
{
// For testing only
if (header.GetFinal() && rand() % 100 < gDropFinalPercent)
{
gLog.Optional(Log::Discard, "Discard packet: TESTING final bit set.");
return false;
}
}
if (header.yourDisc != 0 && header.yourDisc != m_localDiscr)
{
gLog.Optional(Log::Discard, "Discard packet: Source Discriminator is does not match our discriminator.");
return false;
}
if (header.GetAuth())
{
if (packet.auth.GetAuthType() == bfd::AuthType::None)
{
gLog.Optional(Log::Discard, "Discard packet: Auth bit set but type is None.");
return false;
}
// We need to do authentication
gLog.LogWarn("Authentication requested, but we do not handle it currently.");
gLog.Optional(Log::Discard, "Discard packet: Auth bit set and we do not handle it.");
return false;
}
else
{
if (m_authType != bfd::AuthType::None)
{
gLog.Optional(Log::Discard, "Discard packet: Auth bit clear, but session is using authentication.");
return false;
}
}
if (header.GetDemand())
{
{
gLog.Optional(Log::Error, "Discard packet: We do not support demand mode for remote host.");
return false;
}
}
//
// looks like packet can not be discarded after this point
//
m_remoteDesiredMinTxInterval = header.txDesiredMinInt;
m_remoteDetectMult = header.detectMult;
m_remoteDiscr = header.myDisc;
m_remoteSessionState = header.GetState();
m_remoteDemandMode = header.GetDemand();
m_remoteMinRxInterval = header.rxRequiredMinInt;
m_remoteDiag = header.GetDiag();
if (header.rxRequiredMinEchoInt == 0)
{
// We do not handle echo anyway, but if we did, then we would stop.
}
if (header.GetFinal())
{
// Poll sequence, if any, must stop
if (m_pollState != PollState::Polling)
gLog.Optional(Log::Packet, "Unmatched Final bit in packet. ");
else
transitionPollState(PollState::Completed);
}
else
{
// Any poll sequence is now completely finished without ambiguity. (Assuming we
// are in the Competed state now.)
transitionPollState(PollState::None);
}
// Note, the spec has us checking header.GetState(), but that will always
// (currently) be the same as m_remoteSessionState.
LogAssert(m_remoteSessionState == header.GetState());
if (bfd::State::AdminDown == m_remoteSessionState)
setSessionState(bfd::State::Down, bfd::Diag::NeighborSessionDown, SetValueFlags::PreventTxReschedule);
else
{
if (m_sessionState == bfd::State::Down)
{
if (m_remoteSessionState == bfd::State::Down)
setSessionState(bfd::State::Init, bfd::Diag::None, SetValueFlags::PreventTxReschedule);
else if (m_remoteSessionState == bfd::State::Init)
setSessionState(bfd::State::Up, bfd::Diag::None, SetValueFlags::PreventTxReschedule);
}
else if (m_sessionState == bfd::State::Init)
{
if (m_remoteSessionState == bfd::State::Init
|| m_remoteSessionState == bfd::State::Up)
setSessionState(bfd::State::Up, bfd::Diag::None, SetValueFlags::PreventTxReschedule);
}
else if (m_sessionState == bfd::State::Up)
{
if (m_remoteSessionState == bfd::State::Down)
setSessionState(bfd::State::Down, bfd::Diag::NeighborSessionDown, SetValueFlags::PreventTxReschedule);
}
}
// TODO if we wanted to go into demand mode, this is where it would happen
if (isRemoteDemandModeActive())
{
// Cease periodic control packets.
LogVerifyFalse("We do not currently support demand mode");
m_transmitNextTimer->Stop();
}
else if (m_transmitNextTimer->IsStopped())
{
// Start the timer.
scheduleTransmit();
}
if (header.GetPoll())
{
// If poll was received then send a final response asap, "without respect to
// the transmission timer" (v10/6.8.7)
m_pollReceived = true;
sendControlPacket();
}
// If we are active, then we may not yet have a source port
if (m_remoteSourcePort == 0 && m_isActive)
m_remoteSourcePort = port;
else if (m_remoteSourcePort != port)
{
m_remoteSourcePort = port;
gLog.Optional(Log::Session, "Source port has changed for session %u.", m_id);
}
// If we were timing out, we no longer are.
m_timeoutStatus = TimeoutStatus::None;
// Certain changes my require a packet reschedule.
if (m_immediateControlPacket
|| olduseDesiredMinTxInterval != getUseDesiredMinTxInterval()
|| oldRemoteMinRxInterval > m_remoteMinRxInterval // v10/6.8.3p6
|| (oldRemoteMinRxInterval == 0 && oldRemoteMinRxInterval != m_remoteMinRxInterval) // basically the same as above.
)
{
scheduleTransmit();
}
// Packet received ... update Detection time timer
scheduleReceiveTimeout();
return true;
}
/**
* Gets the time between receiving remote control packets that should be
* considered a "timeout".
*
* Returns 0 if we do not expect any packets. (Timeout disabled.)
*
*/
uint64_t Session::getDetectionTimeout()
{
if (getUseRequiredMinRxInterval() == 0)
return 0;
return m_remoteDetectMult * uint64_t(max(getUseRequiredMinRxInterval(), m_remoteDesiredMinTxInterval));
}
/**
* Schedule the next received timeout based on the current settings.
*
*/
void Session::scheduleReceiveTimeout()
{
// Reset received timer (if any) using UpdateMicroTimer()
if (!LogVerify(!m_demandMode))
{
// We currently never set demand mode
return;
}
uint64_t timeout = getDetectionTimeout();
if (timeout == 0)
m_receiveTimeoutTimer->Stop();
else
m_receiveTimeoutTimer->SetMicroTimer(timeout);
}
/**
* Change the received timeout based on the current settings.
*/
void Session::reScheduleReceiveTimeout()
{
// Reset received timer (if any) using UpdateMicroTimer()
if (!LogVerify(!m_demandMode))
{
// We currently never set demand mode
return;
}
uint64_t timeout = getDetectionTimeout();
if (timeout == 0)
m_receiveTimeoutTimer->Stop();
else
m_receiveTimeoutTimer->UpdateMicroTimer(timeout);
}
bool Session::isRemoteDemandModeActive()
{
return (m_remoteDemandMode && m_sessionState == bfd::State::Up && m_remoteSessionState == bfd::State::Up);
}
/**
* Use this to change m_sessionState. Handles the timing of control packets.
*
* @note This may change the MinTXInterval.
*
*
* Set the SetValueFlags::PreventTxReschedule flag is in flags to prevent this
* function from calling scheduleTransmit(). Use only if caller will call
* scheduleTransmit(), or sendControlPacket().
*
* Set the SetValueFlags::TryPoll flag is in flags to start a poll sequence if
* the sate is changed. This is an 'optional' poll sequence, and will be ignored
* if there is already one underway. The poll sequence may be "ambiguous" (see
* transitionPollState)
*
*
* @param newState
* @param diag [in] - The new local diag.
* @param flags [in] - See description above.
*/
void Session::setSessionState(bfd::State::Value newState, bfd::Diag::Value diag, SetValueFlags::Flag flags /*SetValueFlags::None*/)
{
if (m_forcedState)
{
LogOptional(Log::SessionDetail, "(id=%u) Session held at %s no transition to %s", m_id, bfd::StateName(m_sessionState), bfd::StateName(newState));
return;
}
m_localDiag = diag;
if (m_sessionState != newState)
{
LogOptional(Log::Session, "(id=%u) Session transition from %s to %s", m_id, bfd::StateName(m_sessionState), bfd::StateName(newState));
m_sessionState = newState;
logSessionTransition();
if (newState == bfd::State::Up)
{
// Since we are up, we can change to our real DesiredMinTxInterval
if (m_desiredMinTxInterval != m_defaultDesiredMinTxInterval)
setDesiredMinTxInterval(m_defaultDesiredMinTxInterval, (flags & SetValueFlags::PreventTxReschedule));
}
else
{
// According to v10/6.8.3 when state is not up we must have
// m_desiredMinTxInterval at least 1000000
if (m_desiredMinTxInterval < bfd::BaseMinTxInterval)
setDesiredMinTxInterval(bfd::BaseMinTxInterval, (flags & SetValueFlags::PreventTxReschedule));
// If we were waiting for a RequiredMinRxInterval change to finish polling, that
// is now moot.
if (getUseRequiredMinRxInterval() != m_requiredMinRxInterval)
{
// This is Ok here only since we know we are not up.
gLog.Optional(Log::Session, "(id=%u) RequiredMinRxInterval now using new value %u due to session down.", m_id, m_requiredMinRxInterval);
setUseRequiredMinRxInterval(m_requiredMinRxInterval);
reScheduleReceiveTimeout();
}
}
if (SetValueFlags::TryPoll == (flags & SetValueFlags::TryPoll))
transitionPollState(PollState::Requested, true /*allowAmbiguous*/);
// Change in control packets should cause an immediate send (per v10/6.8.7)
m_immediateControlPacket = true;
if ((flags & SetValueFlags::PreventTxReschedule) != SetValueFlags::PreventTxReschedule)
scheduleTransmit(); // schedule immediate transmit.
}
}
/**
* Logs a transition to the current state.
* Stores the transition information for stats.
*/
void Session::logSessionTransition()
{
UptimeInfo *last = NULL;
TimeSpec now(TimeSpec::MonoNow());
// We only log state change when we are fully up.
// The state machine does not allow up->init transition, so we must have been
// down (and we still count this as down).
if (m_sessionState == bfd::State::Init)
return;
// Check if we even need to log the state transition
if (!m_uptimeList.empty())
{
last = &m_uptimeList.front();
// only log when state changes.
if (last->state == m_sessionState)
{
if (m_forcedState && !last->forced)
last->forced = m_forcedState;
return;
}
// If we go Down->AdminDown, then just call it that.
if (last->state == bfd::State::Down && m_sessionState == bfd::State::AdminDown)
{
last->state = bfd::State::AdminDown;
last->forced = m_forcedState;
return;
}
}
GetMonolithicTime(now);
if (last)
last->endTime = now;
// log the new state
UptimeInfo uptime;
uptime.state = m_sessionState;
uptime.startTime = now;
uptime.forced = false; // currently not using this.
try
{
m_uptimeList.push_front(uptime);
}
catch (std::exception)
{
// TODO - could mark the whole thing as "invalid"?
m_uptimeList.clear();
}
if (m_uptimeList.size() > MaxUptimeCount)
m_uptimeList.pop_back();
}
/**
* Called to attempt to transition poll state. Enforces linear transitions.
*
* @param nextState
* @param allowAmbiguous - If true, then we can start a new poll sequence even if
* the previous one just ended. The poll sequence will be
* "ambiguous" as described in v10/6/8/3p9. This should be
* used only if the caller does not need to take any
* action when the poll completes.
*
* @return - false if the transition was not valid.
*/
bool Session::transitionPollState(PollState::Value nextState, bool allowAmbiguous /*false*/)
{
// This is used to track polling. In particular, we can not start two separate
// polls too close together or they become ambiguous as described at the end of
// v10/6.8.3. Currently we require a non-F response in between to disambiguate
// poll. We could also add a timing element as described in that section, if
// needed.
if (nextState == PollState::None)
{
if (m_pollState == PollState::None)
return true;
if (m_pollState == PollState::Completed)
{
// Poll sequence is now unambiguously finished. We can now start a new one if we
// want.
m_pollState = PollState::None;
if (m_wantsPollForNewDesiredMinTxInterval
|| m_wantsPollForNewRequiredMinRxInterval
)
return transitionPollState(PollState::Requested);
return true;
}
return false;
}
else if (nextState == PollState::Requested)
{
if (m_pollState == PollState::Requested || m_pollState == PollState::None)
{
m_pollState = PollState::Requested;
// If either of these were true, then we can set them to false now, since they
// will automatically take effect at the end of this poll sequence.
m_wantsPollForNewDesiredMinTxInterval = false;
m_wantsPollForNewRequiredMinRxInterval = false;
// If we are not transmitting (perhaps m_remoteMinRxInterval == 0) then we need
// to now to make polling happen. Note that this will still wait until the
// "next" transmit, even though that might not be required in all cases.
if (m_transmitNextTimer->IsStopped())
scheduleTransmit();
return true;
}
if (m_pollState == PollState::Completed && allowAmbiguous)
{
m_pollState = PollState::None;
return transitionPollState(PollState::Requested);
}
return false;
}
else if (nextState == PollState::Polling)
{
if (m_pollState == PollState::Requested || m_pollState == PollState::None)
{
m_pollState = PollState::Polling;
return true;
}
return false;
}
else if (nextState == PollState::Completed)
{
if (m_pollState == PollState::Polling)
{
m_pollState = PollState::Completed;
// Handle any changes that need to be made after polling.
// we can use the m_desiredMinTxInterval once the poll has completed, unless we
// want another poll for that purpose.
if (!m_wantsPollForNewDesiredMinTxInterval)
setUseDesiredMinTxInterval(m_desiredMinTxInterval);
// we can use the m_requiredMinRxInterval once the poll has completed, unless we
// want another poll for that purpose.
if (!m_wantsPollForNewRequiredMinRxInterval && getUseRequiredMinRxInterval() != m_requiredMinRxInterval)
{
setUseRequiredMinRxInterval(m_requiredMinRxInterval);
reScheduleReceiveTimeout();
}
// If we are only sending packets as part of a poll then we can stop now.
if (!m_transmitNextTimer->IsStopped() && getBaseTransmitTime() == 0)
scheduleTransmit();
return true;
}
return false;
}
LogVerify(false);
return false;
}
/**
* Schedules the next packet transmission based on current state.
* Poll response packets are not scheduled, and so are not handled here.
*/
void Session::scheduleTransmit()
{
uint64_t transmitInterval = 0;
// Poll packet responses are handled immediately, so this routine should not be
// involved.
LogAssert(!m_pollReceived);
if (m_immediateControlPacket)
{
// On certain changes we need to send an immediate packet
m_transmitNextTimer->SetMicroTimer(0);
return;
}
if (!m_isActive && m_remoteDiscr == 0)
{
m_transmitNextTimer->Stop();
return; // Passive session.
}
// We recalculate the transmit interval every time, which may mean a little
// extra "churning" on the timer.
transmitInterval = getBaseTransmitTime();
if (transmitInterval == 0)
{
bool sendPoll = (m_pollState == PollState::Requested || m_pollState == PollState::Polling);
// If we are not polling, then no packets get sent.
if (!sendPoll)
{
m_transmitNextTimer->Stop();
return;
}
else
{
// We are polling, but we have demand mode (not supported anyway) or
// m_remoteMinRxInterval of 0 (not handled properly by JUNOS 8.5)
// So we just keep transmitting until we get a poll response. The timing is not
// spelled out in the spec. TODO: still verifying that this is a reasonable
// approach.
transmitInterval = getUseDesiredMinTxInterval();
}
}
// Apply jitter
transmitInterval = uint64_t(transmitInterval * (0.75 + 0.25 * double(rand()) / RAND_MAX));
// Limits on jitter
if (m_detectMult == 1)
{
if (transmitInterval > uint64_t(0.90 * transmitInterval))
transmitInterval = uint64_t(0.90 * transmitInterval);
}
m_transmitNextTimer->UpdateMicroTimer(transmitInterval);
}
/**
*
* Gets the base time for transmitting periodic control packets.
*
* @return uint32_t - 0 if no packets are being sent.
*/
uint32_t Session::getBaseTransmitTime()
{
if (!m_isActive && m_remoteDiscr == 0)
return 0; // Passive session.
if (m_remoteMinRxInterval == 0)
return 0; // no periodic
// Note, we do not handle this anyway.
if (isRemoteDemandModeActive())
return 0; // no periodic
return max(getUseDesiredMinTxInterval(), m_remoteMinRxInterval);
}
/**
* Sends a control packet. Does not update timers.
* @note Must be called from main thread.
*
*/
void Session::sendControlPacket()
{
bool poll;
poll = (!m_pollReceived && (m_pollState == PollState::Requested || m_pollState == PollState::Polling));
BfdPacket packet = BfdPacket();
BfdPacketHeader &header = packet.header;
header.SetVersion(bfd::Version);
header.length = sizeof(header);
header.SetDiag(m_localDiag);
header.SetState(m_sessionState);
header.SetPoll(poll);
header.SetFinal(m_pollReceived);
header.SetControlPlaneIndependent(m_controlPlaneIndependent);
// The next few are always false, so we could skip setting them. Included for
// completeness.
header.SetAuth(false); // never for now.
header.SetDemand(false); // never for now.
header.SetMultipoint(false), // never
header.detectMult = m_detectMult;
header.myDisc = htonl(m_localDiscr);
header.yourDisc = htonl(m_remoteDiscr);
header.txDesiredMinInt = htonl(m_desiredMinTxInterval);
header.rxRequiredMinInt = htonl(m_requiredMinRxInterval);
header.rxRequiredMinEchoInt = htonl(0); // no echo allowed for this system.
// Since we will have tried to send a poll response, we are done unless we get another.
m_pollReceived = false;
// Since we are attempting to send the packet, we have fulfilled m_immediateControlPacket
m_immediateControlPacket = false;
if (!ensureSendSocket())
return;
send(packet);
if (poll)
transitionPollState(PollState::Polling);
}
/**
* Sends the given packet.
*
* @note Must be called from main thread.
*
* @param packet
*/
void Session::send(const BfdPacket &packet)
{
if (!ensureSendSocket())
return;
if (m_isSuspended)
{
gLog.Optional(Log::Packet, "Not sending packet for suspended session %u.", m_id);
return;
}
logPacketContents(packet, true, false, m_remoteAddr, 0, m_localAddr, m_sendPort);
if (m_sendSocket.SendTo(&packet, packet.header.length,
SockAddr(m_remoteAddr, bfd::ListenPort),
MSG_NOSIGNAL))
gLog.Optional(Log::Packet, "Sent control packet for session %u.", m_id);
}
/**
* Attempts to connect the m_sendSocket send socket, if there is not one
* already.
*
* @return bool - false if the socket could not be opened.
*/
bool Session::ensureSendSocket()
{
uint16_t startPort;
Socket sendSocket;
SockAddr sendAddr;
if (!m_sendSocket.empty())
return true;
m_sendSocket.SetExpectedVerbosity(Log::Warn);
if (!LogVerify(m_localAddr.IsValid()))
return false;
if (!LogVerify(!m_localAddr.IsAny()))
return false;
char tmp[255];
sendSocket.SetLogName(FormatStr(tmp, sizeof(tmp), "Session %d sock", m_id));
// Note that all sockets will log errors, so we do not have to.
if (!sendSocket.OpenUDP(m_localAddr.Type()))
return false;
if (!sendSocket.SetTTLOrHops(bfd::TTLValue))
return false;
/* Find an available port in the proper range */
if (m_sendPort != 0)
startPort = m_sendPort;
else
startPort = bfd::MinSourcePort + rand() % (bfd::MaxSourcePort - bfd::MinSourcePort);
sendAddr = SockAddr(m_localAddr, startPort);
// We need the socket to be quiet so we do not get warnings for each port tried.
RaiiObjCallVar<bool, Socket, bool, &Socket::SetQuiet> m_socketQuiet(&sendSocket);
m_socketQuiet = sendSocket.SetQuiet(true);
while (!sendSocket.Bind(sendAddr))
{
switch (sendSocket.GetLastError())
{
default:
gLog.LogError("Unable to open socket for session %" PRIu32 " %s : (%d) %s",
m_id, sendAddr.ToString(false),
sendSocket.GetLastError(), SystemErrorToString(sendSocket.GetLastError()));
return false;
break;
case EAGAIN:
case EADDRINUSE:
// Fall through and keep looking
break;
}
if (sendAddr.Port() == bfd::MaxSourcePort)
sendAddr.SetPort(bfd::MinSourcePort);
else
sendAddr.SetPort(sendAddr.Port() + 1);
if (sendAddr.Port() == startPort)
{
gLog.LogError("Cant find valid send port.");
return false;
}