Retro68/LaunchAPPL/Common/ReliableStream.cc

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#include "ReliableStream.h"
#include <iterator>
#include "CRC32.h"
using std::begin;
using std::end;
const uint8_t magic1[4] = { 0xDE, 0xAD, 0xBE, 0xEF };
const uint8_t magic2[4] = { 0xFA, 0xCE, 0xCA, 0xFE };
const uint32_t magic1_32 = 0xDEADBEEF;
const uint32_t magic2_32 = 0xFACECAFE;
enum thing : uint8_t
{
kDataPacket = 0,
kEndOfPacket,
kEscapedMagic1,
kEscapedMagic2,
kAck,
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kNack,
kReset1,
kReset2
};
inline uint32_t readLong(uint8_t* p)
{
uint32_t x;
x = *p++;
x = (x << 8) | *p++;
x = (x << 8) | *p++;
x = (x << 8) | *p++;
return x;
}
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ReliableStream::ReliableStream(Stream* stream)
: StreamWrapper(stream)
{
incomingPacket.reserve(packetSize + 4);
}
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void ReliableStream::reset(int sendReset)
{
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//printf("reset %d\n", sendReset);
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receivedInputPacket = 0;
sentOutputPacket = 0;
ackedOutputPacket = 0;
failedReceiveCount = failedSendCount = 0;
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incomingPacket.clear();
state = State::waiting;
sentPackets.clear();
packetsToSend.clear();
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resetResponse = false;
if(sendReset)
{
uint8_t resetKind = sendReset == 1 ? kReset1 : kReset2;
uint8_t packet[] = {
magic1[0], magic1[1], magic1[2], magic1[3],
resetKind, (uint8_t)~resetKind
};
underlying().write(packet, 6);
}
}
void ReliableStream::ack()
{
uint8_t packet[] = {
magic1[0], magic1[1], magic1[2], magic1[3],
kAck, (uint8_t)~kAck, (uint8_t)receivedInputPacket, (uint8_t)~receivedInputPacket
};
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underlying().write(packet, 8);
//printf("ack sent\n");
}
void ReliableStream::nack()
{
uint8_t packet[] = {
magic1[0], magic1[1], magic1[2], magic1[3],
kNack, (uint8_t)~kNack, (uint8_t)receivedInputPacket, (uint8_t)~receivedInputPacket
};
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underlying().write(packet, 8);
//printf("nack sent\n");
failedReceiveCount++;
}
void ReliableStream::gotAck(uint8_t id)
{
unsigned nAcked = (id - ackedOutputPacket) & 0xFF;
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//printf("got ack %d -> %u packets of %u acked\n", (int)id, nAcked, (unsigned)sentPackets.size());
if(nAcked <= sentPackets.size())
{
ackedOutputPacket += nAcked;
for(int i = 0; i < nAcked; i++)
sentPackets.pop_front();
sendPackets();
}
}
void ReliableStream::gotNack(uint8_t id)
{
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//printf("got nack %d\n", (int)id);
unsigned nAcked = (id - ackedOutputPacket) & 0xFF;
if(nAcked <= sentPackets.size())
{
ackedOutputPacket += nAcked;
for(int i = 0; i < nAcked; i++)
sentPackets.pop_front();
sentOutputPacket = ackedOutputPacket;
failedSendCount += packetsToSend.size();
packetsToSend.splice(packetsToSend.begin(), sentPackets);
sendPackets();
}
}
void ReliableStream::processIncoming()
{
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//printf("Received packet %d - %d bytes\n", receivedInputPacket + 1, (int)incomingPacket.size());
if(incomingPacket.size() < 4)
{
nack();
incomingPacket.clear();
return;
}
uint32_t expectedCRC = crc32(0, incomingPacket.begin(), incomingPacket.end() - 4);
uint32_t receivedCRC = readLong(&incomingPacket[incomingPacket.size()-4]);
if(receivedCRC != expectedCRC)
{
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//printf("CRC mismatch %x != %x\n", receivedCRC, expectedCRC);
nack();
incomingPacket.clear();
return;
}
receivedInputPacket++;
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//printf("Verified packet %d - %d bytes\n", receivedInputPacket, (int)incomingPacket.size());
ack();
notifyReceive(incomingPacket.data(), incomingPacket.size() - 4);
incomingPacket.clear();
}
void ReliableStream::sendOnePacket()
{
if(packetsToSend.empty())
return;
const uint8_t* p = packetsToSend.front().data();
size_t n = packetsToSend.front().size();
if(n < packetSize)
flushRequested = false;
++sentOutputPacket;
sentPackets.splice(sentPackets.end(), packetsToSend, packetsToSend.begin());
std::vector<uint8_t> packet;
packet.reserve(n + 32);
packet = {
magic1[0], magic1[1], magic1[2], magic1[3],
kDataPacket, (uint8_t)~kDataPacket, (uint8_t)sentOutputPacket, (uint8_t)~sentOutputPacket
};
int match = 0, match2 = 0;
int i;
int consumed = 0;
for(i = 0; i < n; i++)
{
if(p[i] == magic1[match])
match++;
else if(p[i] == magic1[0])
match = 1;
else
match = 0;
if(match == 4)
{
packet.push_back(magic2[0]);
packet.push_back(magic2[1]);
packet.push_back(magic2[2]);
packet.push_back(magic2[3]);
packet.push_back(kEscapedMagic1);
match = 0;
consumed = i+1;
}
if(match == 0)
while(consumed <= i)
packet.push_back(p[consumed++]);
if(p[i] == magic2[match2])
match2++;
else if(p[i] == magic2[0])
match2 = 1;
else
match2 = 0;
if(match2 == 4)
{
match2 = 0;
packet.push_back(kEscapedMagic2);
}
}
while(consumed < i)
packet.push_back(p[consumed++]);
packet.push_back(magic2[0]);
packet.push_back(magic2[1]);
packet.push_back(magic2[2]);
packet.push_back(magic2[3]);
packet.push_back(kEndOfPacket);
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//printf("sent packet: %d, total %d bytes\n", sentOutputPacket, (int)packet.size());
//printf("sendOnePacket: %d - %d packets, next = %d\n", (int)packetsToSend.size(), (int)sentPackets.size(), sentOutputPacket + 1);
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underlying().write(packet.data(), packet.size());
}
void ReliableStream::sendPackets()
{
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//printf("sendPackets: %d - %d packets, next = %d\n", (int)packetsToSend.size(), (int)sentPackets.size(), sentOutputPacket + 1);
while(!packetsToSend.empty() && sentPackets.size() < maxInFlight
&& (flushRequested || sentPackets.front().size() >= packetSize))
sendOnePacket();
}
void ReliableStream::flushWrite()
{
flushRequested = true;
sendPackets();
}
void ReliableStream::write(const void* p, size_t n)
{
while(n)
{
size_t availableSpaceInPacket = 0;
if(!packetsToSend.empty())
availableSpaceInPacket = packetSize - (packetsToSend.back().size()-4);
uint32_t crc = 0;
if(availableSpaceInPacket)
{
auto& packet = packetsToSend.back();
auto p = packet.end() - 4;
crc = (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
packet.erase(p, packet.end());
}
else
{
packetsToSend.emplace_back();
availableSpaceInPacket = packetSize;
flushRequested = false;
}
size_t n1 = n > availableSpaceInPacket ? availableSpaceInPacket : n;
auto& packet = packetsToSend.back();
packet.reserve(packetSize + 4);
auto newData = packet.end();
packet.insert(newData, (const uint8_t*)p, ((const uint8_t*)p)+n1);
crc = crc32(crc, newData, packet.end());
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//printf("outgoing crc: %x (bytes: %d without crc and header)\n", (unsigned) crc, (int)packet.size());
packet.push_back(crc >> 24);
packet.push_back(crc >> 16);
packet.push_back(crc >> 8);
packet.push_back(crc);
p = ((const uint8_t*)p) + n1;
n -= n1;
}
flushWrite();
}
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//#include <MacTypes.h>
size_t ReliableStream::onReceive(const uint8_t* p, size_t n)
{
//printf("data available (%d) - state %d\n", (int)n, (int)state);
switch(state)
{
case State::waiting:
if( (n > 0 && p[0] != magic1[0])
|| (n > 1 && p[1] != magic1[1])
|| (n > 2 && p[2] != magic1[2])
|| (n > 3 && p[3] != magic1[3]) )
{
state = State::skipping;
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//printf("no magic\n");
nack();
gotNack(ackedOutputPacket);
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if(p[0] != magic1[0])
return 0;
else if(p[1] != magic1[1])
return 1;
else if(p[2] != magic1[2])
return 2;
else
return 3;
}
if(n < 6)
return 0;
if(p[5] != (uint8_t)~p[4])
{
state = State::skipping;
nack();
gotNack(ackedOutputPacket);
return 6;
}
switch(p[4])
{
case kAck:
if(n < 8)
return 0;
if(p[6] != (uint8_t)~p[7])
{
state = State::skipping;
nack();
gotNack(ackedOutputPacket);
return 8;
}
gotAck(p[6]);
return 8;
case kNack:
if(n < 8)
return 0;
if(p[6] != (uint8_t)~p[7])
{
state = State::skipping;
nack();
gotNack(ackedOutputPacket);
return 8;
}
gotNack(p[6]);
return 8;
case kDataPacket:
if(n < 8)
return 0;
if(p[6] != (uint8_t)~p[7])
{
state = State::skipping;
nack();
gotNack(ackedOutputPacket);
return 8;
}
if(p[6] != ((receivedInputPacket + 1) & 0xFF))
{
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//printf("bad serial: %d %d\n", p[6], receivedInputPacket+1);
//nack();
state = State::skipping;
return 8;
}
state = State::receiving;
inputMatchMagic1 = inputMatchMagic2 = 0;
return 8;
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case kReset1:
reset(2);
notifyReset();
return 6;
case kReset2:
reset(0);
resetResponse = true;
notifyReset();
return 6;
default:
state = State::skipping;
nack();
gotNack(ackedOutputPacket);
return 8;
}
break;
case State::skipping:
{
int match = 0;
int i;
for(i = 0; i < n; i++)
{
if(p[i] == magic1[match++])
{
if(match == 4)
{
state = State::waiting;
return i-3;
}
}
else
match = 0;
}
return i - match;
}
break;
case State::receiving:
{
int i;
for(i = 0; i < n; i++)
{
incomingPacket.push_back(p[i]);
if(inputMatchMagic2 == 4)
{
inputMatchMagic2 = 0;
incomingPacket.pop_back();
switch(p[i])
{
case kEscapedMagic1:
std::copy(begin(magic1), end(magic1), incomingPacket.end()-4);
break;
case kEscapedMagic2:
break;
case kEndOfPacket:
incomingPacket.erase(incomingPacket.end()-4, incomingPacket.end());
processIncoming();
state = State::waiting;
return i + 1;
default:
state = State::waiting;
nack();
return i + 1;
}
}
if(p[i] != magic1[inputMatchMagic1])
inputMatchMagic1 = 0;
if(p[i] == magic1[inputMatchMagic1])
inputMatchMagic1++;
if(p[i] != magic2[inputMatchMagic2])
inputMatchMagic2 = 0;
if(p[i] == magic2[inputMatchMagic2])
inputMatchMagic2++;
if(inputMatchMagic1 == 4)
{
state = State::waiting;
nack();
return i-3;
}
}
return n;
}
break;
}
}