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Implement peer-MSS based implementation #47

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693ec94
Increment pt_cursor only when a port is actually allocated
adpp00 Nov 19, 2025
b9746b3
Add peer-MSS based logic and fix option-parsing bug in rx_engine
adpp00 Nov 20, 2025
5299ad5
Fix: split packets based on mss_rounddown (peer MSS rounded down to 64B)
adpp00 Nov 21, 2025
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14 changes: 8 additions & 6 deletions hls/toe/port_table/port_table.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -137,16 +137,18 @@ void free_port_table( stream<ap_uint<16> >& sLookup2portTable_releasePort,
}
else
{
if (!freePortTable[pt_cursor] && !portTable2txApp_port_rsp.full()) //This is not perfect, but yeah
{
freePort(14, 0) = pt_cursor;
freePort[15] = 1;
bool used = freePortTable[pt_cursor];
if (used) {
pt_cursor++;
} else if (!portTable2txApp_port_rsp.full()) {
ap_uint<16> freePort;
freePort(14,0) = pt_cursor;
freePort[15] = 1;
freePortTable[pt_cursor] = true;
portTable2txApp_port_rsp.write(freePort);
pt_cursor++;
}
}
pt_cursor++;

/*if (!txApp2portTable_port_req.empty()) //Fixme this!!!
{
txApp2portTable_port_req.read();
Expand Down
80 changes: 60 additions & 20 deletions hls/toe/rx_engine/rx_engine.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -638,30 +638,37 @@ void drop_optional_header_fields( hls::stream<optionalFieldsMeta>& metaIn,
* kind | length | description
* 0 | 1B | End of options list
* 1 | 1B | NOP/Padding
* 2 | 4B | MSS (Maximum segment size)
* 2 | 4B | MSS (Maximum segment size) - If omitted, 536B for IPv4
* 3 | 3B | Window scale
* 4 | 2B | SACK permitted (Selective Acknowledgment)
*/
void parse_optional_header_fields( hls::stream<ap_uint<4> >& dataOffsetIn,
hls::stream<ap_uint<320> >& optionalHeaderFieldsIn,
hls::stream<ap_uint<4> >& windowScaleOut)
hls::stream<ap_uint<4> >& windowScaleOut,
hls::stream<ap_uint<16> >& mssOut)
{
#pragma HLS PIPELINE II=1
#pragma HLS INLINE off

enum fsmStateType {IDLE, PARSE};
static fsmStateType state = IDLE;
static ap_uint<4> dataOffset;
static ap_uint<4> dataOffsetDword;
static ap_uint<6> dataOffsetByte;
static ap_uint<320> fields;
static bool got_ws = false;
static bool got_mss = false;

switch (state)
{
case IDLE:
if (!dataOffsetIn.empty() && !optionalHeaderFieldsIn.empty())
{
// std::cout << "PARSE IDLE" << std::endl;
dataOffsetIn.read(dataOffset);
dataOffsetIn.read(dataOffsetDword);
dataOffsetByte = 4 * (ap_int<6>)dataOffsetDword;
optionalHeaderFieldsIn.read(fields);
got_ws = false;
got_mss = false;
state = PARSE;
}
break;
Expand All @@ -671,35 +678,64 @@ void parse_optional_header_fields( hls::stream<ap_uint<4> >& dataOffsetIn,

switch (optionKind)
{
case 0: //End of option list
windowScaleOut.write(0);
case 0:{//End of option list
if(!got_mss) mssOut.write(536);
if(!got_ws) windowScaleOut.write(0);
// std::cout << "PARSE EOL" << std::endl;
state = IDLE;
break;
case 1:
optionLength = 1;
}
case 1:{ // NOP
if(dataOffsetByte == 1){
if(!got_mss) mssOut.write(536);
if(!got_ws) windowScaleOut.write(0);
state = IDLE;
}
else optionLength = 1;
break;
case 3:
}
case 2:{
ap_uint<16> mss;
mss(15,8) = fields(23,16);
mss( 7,0) = fields(31,24);
mssOut.write(mss);
if (dataOffsetByte == 4 || got_ws){
if(!got_ws) windowScaleOut.write(0);
state = IDLE;
}
got_mss = true;
optionLength = 4;
break;
}
case 3:{
// std::cout << "PARSE WS: " << (uint16_t)fields(19, 16) << std::endl;
windowScaleOut.write(fields(19, 16));
state = IDLE;
if (dataOffsetByte == 3 || got_mss){
if(!got_mss) mssOut.write((ap_uint<16>)536);
state = IDLE;
}
optionLength = 3;
got_ws = true;
break;
default:
if (dataOffset == optionLength)
{
windowScaleOut.write(0);
}
default:{
if(dataOffsetByte == optionLength){
if(!got_mss) mssOut.write((ap_uint<16>)536);
if(!got_ws) windowScaleOut.write(0);
// std::cout << "PARSE DONE" << std::endl;
state = IDLE;
}
break;
}
}//switch
dataOffset -= optionLength;
dataOffsetByte -= optionLength;
fields = (fields >> (optionLength*8));
break;
}//switch
}

void merge_header_meta(hls::stream<ap_uint<4> >& rxEng_winScaleFifo,
hls::stream<ap_uint<16> >& rxEng_mssFifo,
hls::stream<rxEngineMetaData>& rxEng_headerMetaFifo,
hls::stream<rxEngineMetaData>& rxEng_metaDataFifo)
{
Expand All @@ -723,15 +759,17 @@ void merge_header_meta(hls::stream<ap_uint<4> >& rxEng_winScaleFifo,
else
{
meta.winScale = 0;
meta.mss = 536;
rxEng_metaDataFifo.write(meta);
}
}
break;
case 1:
if (!rxEng_winScaleFifo.empty())
if (!rxEng_winScaleFifo.empty() && !rxEng_mssFifo.empty())
{
// std::cout << "META MERGE 1" << std::endl;
meta.winScale = rxEng_winScaleFifo.read();
meta.mss = rxEng_mssFifo.read();
rxEng_metaDataFifo.write(meta);
state = 0;
}
Expand Down Expand Up @@ -1368,7 +1406,7 @@ void rxTcpFSM( stream<rxFsmMetaData>& fsmMetaDataFifo,
// Initialize rxSar, SEQ + phantom byte for recvd and head pointer, offset to 0, gap set to false
rxEng2rxSar_upd_req.write(rxSarRecvd(fsm_meta.sessionID, fsm_meta.meta.seqNumb+1, fsm_meta.meta.seqNumb+1, 0, false, rx_win_shift));
// Initialize receive window
rxEng2txSar_upd_req.write((rxTxSarQuery(fsm_meta.sessionID, 0, fsm_meta.meta.winSize, txSar.cong_window, 0, false, tx_win_shift))); //TODO maybe include count check
rxEng2txSar_upd_req.write((rxTxSarQuery(fsm_meta.sessionID, 0, fsm_meta.meta.winSize, txSar.cong_window, 0, false, tx_win_shift, fsm_meta.meta.mss))); //TODO maybe include count check
#else
// Initialize rxSar, SEQ + phantom byte, last '1' for makes sure appd is initialized
rxEng2rxSar_upd_req.write(rxSarRecvd(fsm_meta.sessionID, fsm_meta.meta.seqNumb+1, fsm_meta.meta.seqNumb+1, 0, false, 1));
Expand Down Expand Up @@ -1432,7 +1470,7 @@ void rxTcpFSM( stream<rxFsmMetaData>& fsmMetaDataFifo,
ap_uint<4> rx_win_shift = (fsm_meta.meta.winScale == 0) ? 0 : WINDOW_SCALE_BITS;
ap_uint<4> tx_win_shift = fsm_meta.meta.winScale;
rxEng2rxSar_upd_req.write(rxSarRecvd(fsm_meta.sessionID, fsm_meta.meta.seqNumb+1, fsm_meta.meta.seqNumb+1, 0, false, rx_win_shift));
rxEng2txSar_upd_req.write((rxTxSarQuery(fsm_meta.sessionID, fsm_meta.meta.ackNumb, fsm_meta.meta.winSize, txSar.cong_window, 0, false, tx_win_shift))); //TODO maybe include count check
rxEng2txSar_upd_req.write((rxTxSarQuery(fsm_meta.sessionID, fsm_meta.meta.ackNumb, fsm_meta.meta.winSize, txSar.cong_window, 0, false, tx_win_shift, fsm_meta.meta.mss))); //TODO maybe include count check
#else
//initialize rx_sar, SEQ + phantom byte, last '1' for appd init
rxEng2rxSar_upd_req.write(rxSarRecvd(fsm_meta.sessionID, fsm_meta.meta.seqNumb+1, fsm_meta.meta.seqNumb+1, 0, false, 1));
Expand Down Expand Up @@ -2103,10 +2141,12 @@ void rx_engine( stream<net_axis<WIDTH> >& ipRxData,
static hls::stream<ap_uint<4> > rxEng_dataOffsetFifo("rxEng_dataOffsetFifo");
static hls::stream<ap_uint<320> > rxEng_optionalFieldsFifo("rxEng_optionalFieldsFifo");
static hls::stream<ap_uint<4> > rxEng_winScaleFifo("rxEng_winScaleFifo");
static hls::stream<ap_uint<16> > rxEng_mssFifo("rxEng_mssFifo");
#pragma HLS stream variable=rxEng_headerMetaFifo depth=16
#pragma HLS stream variable=rxEng_dataOffsetFifo depth=2
#pragma HLS stream variable=rxEng_optionalFieldsFifo depth=2
#pragma HLS stream variable=rxEng_winScaleFifo depth=2
#pragma HLS stream variable=rxEng_mssFifo depth=2
//TODO data pack
#endif

Expand Down Expand Up @@ -2136,8 +2176,8 @@ void rx_engine( stream<net_axis<WIDTH> >& ipRxData,
//rxTcpInvalidDropper<WIDTH>(rxEng_dataBuffer3b, rxEng_tcpValidFifo, rxEng_dataBuffer3);

#if (WINDOW_SCALE)
parse_optional_header_fields(rxEng_dataOffsetFifo, rxEng_optionalFieldsFifo, rxEng_winScaleFifo);
merge_header_meta(rxEng_winScaleFifo, rxEng_headerMetaFifo, rxEng_metaDataFifo);
parse_optional_header_fields(rxEng_dataOffsetFifo, rxEng_optionalFieldsFifo, rxEng_winScaleFifo, rxEng_mssFifo);
merge_header_meta(rxEng_winScaleFifo, rxEng_mssFifo, rxEng_headerMetaFifo, rxEng_metaDataFifo);
#endif

rxMetadataHandler( rxEng_metaDataFifo,
Expand Down
1 change: 1 addition & 0 deletions hls/toe/rx_engine/rx_engine.hpp
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Expand Up @@ -66,6 +66,7 @@ struct rxEngineMetaData
ap_uint<1> fin;
ap_uint<4> dataOffset;
//ap_uint<16> dstPort;
ap_uint<16> mss; // peer MSS
};

/** @ingroup rx_engine
Expand Down
30 changes: 27 additions & 3 deletions hls/toe/toe_internals.hpp
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Expand Up @@ -185,6 +185,7 @@ struct txSarEntry
ap_uint<16> recv_window;
#if (WINDOW_SCALE)
ap_uint<4> win_shift;
ap_uint<16> peer_mss;
#endif
ap_uint<WINDOW_BITS> cong_window;
ap_uint<WINDOW_BITS> slowstart_threshold;
Expand All @@ -205,6 +206,7 @@ struct rxTxSarQuery
bool fastRetransmitted;
#if (WINDOW_SCALE)
ap_uint<4> win_shift;
ap_uint<16> peer_mss;
#endif
ap_uint<1> write;
ap_uint<1> init;
Expand All @@ -215,7 +217,9 @@ struct rxTxSarQuery
:sessionID(id), ackd(ackd), recv_window(recv_win), cong_window(cong_win), count(count), fastRetransmitted(fastRetransmitted), write(1), init(0) {}
#if (WINDOW_SCALE)
rxTxSarQuery(ap_uint<16> id, ap_uint<32> ackd, ap_uint<16> recv_win, ap_uint<WINDOW_BITS> cong_win, ap_uint<2> count, bool fastRetransmitted, ap_uint<4> win_shift)
:sessionID(id), ackd(ackd), recv_window(recv_win), cong_window(cong_win), count(count), fastRetransmitted(fastRetransmitted), win_shift(win_shift), write(1), init(1) {}
:sessionID(id), ackd(ackd), recv_window(recv_win), cong_window(cong_win), count(count), fastRetransmitted(fastRetransmitted), win_shift(win_shift), write(1), init(1), peer_mss(0) {}
rxTxSarQuery(ap_uint<16> id, ap_uint<32> ackd, ap_uint<16> recv_win, ap_uint<WINDOW_BITS> cong_win, ap_uint<2> count, bool fastRetransmitted, ap_uint<4> win_shift, ap_uint<16> peer_mss)
:sessionID(id), ackd(ackd), recv_window(recv_win), cong_window(cong_win), count(count), fastRetransmitted(fastRetransmitted), win_shift(win_shift), write(1), init(1), peer_mss(peer_mss) {}
#endif
};

Expand All @@ -241,6 +245,17 @@ struct txTxSarQuery
:sessionID(id), not_ackd(not_ackd), write(write), init(init), finReady(finReady), finSent(finSent), isRtQuery(isRt) {}
};

struct txDDRbypassPush
{
bool isBypass;
ap_uint<16> session_mss;
txDDRbypassPush() {}
txDDRbypassPush(bool en)
:isBypass(en),session_mss(576) {}
txDDRbypassPush(bool en, ap_uint<16> mss)
:isBypass(en),session_mss(mss) {}
};

struct txTxSarRtQuery : public txTxSarQuery
{
txTxSarRtQuery() {}
Expand Down Expand Up @@ -338,12 +353,21 @@ struct txTxSarReply
ap_uint<WINDOW_BITS> usedLength;
bool finReady;
bool finSent;
//#if (WINDOW_SCALE)
ap_uint<4> win_shift;
//#endif
#if (WINDOW_SCALE)
ap_uint<16> peer_mss;
#endif
txTxSarReply() {}
#if (WINDOW_SCALE)
txTxSarReply(ap_uint<32> ack, ap_uint<32> nack, ap_uint<WINDOW_BITS> usableWindow, ap_uint<WINDOW_BITS> app, ap_uint<WINDOW_BITS> usedLength, bool finReady, bool finSent)
:ackd(ack), not_ackd(nack), usableWindow(usableWindow), app(app), usedLength(usedLength), finReady(finReady), finSent(finSent), peer_mss(0) {}
txTxSarReply(ap_uint<32> ack, ap_uint<32> nack, ap_uint<WINDOW_BITS> usableWindow, ap_uint<WINDOW_BITS> app, ap_uint<WINDOW_BITS> usedLength, bool finReady, bool finSent, ap_uint<16> peer_mss)
:ackd(ack), not_ackd(nack), usableWindow(usableWindow), app(app), usedLength(usedLength), finReady(finReady), finSent(finSent), peer_mss(peer_mss) {}
#else
txTxSarReply(ap_uint<32> ack, ap_uint<32> nack, ap_uint<WINDOW_BITS> usableWindow, ap_uint<WINDOW_BITS> app, ap_uint<WINDOW_BITS> usedLength, bool finReady, bool finSent)
:ackd(ack), not_ackd(nack), usableWindow(usableWindow), app(app), usedLength(usedLength), finReady(finReady), finSent(finSent) {}
#endif

};

struct rxRetransmitTimerUpdate {
Expand Down
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