Andrew Boyson / net

A stack which works with or without an Mbed os library. Provides IPv4 or IPv6 with a full 1500 byte buffer.

Dependents:   oldheating gps motorhome heating

tcp/tcprecv.c@93:580fc113d9e9, 2018-12-02 (annotated)

Committer:
andrewboyson
Date:
Sun Dec 02 18:40:35 2018 +0000
Revision:
93:580fc113d9e9
Parent:
91:879545b19260
Child:
96:43eb7a110f1a
Removed ClockTick and replaced with ms timer.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 74:c3756bfa960e 1 #include <stdint.h>
andrewboyson 74:c3756bfa960e 2 #include <stdbool.h>
andrewboyson 75:603b10404183 3 #include <stdarg.h>
andrewboyson 74:c3756bfa960e 4
andrewboyson 74:c3756bfa960e 5 #include "log.h"
andrewboyson 74:c3756bfa960e 6 #include "net.h"
andrewboyson 74:c3756bfa960e 7 #include "action.h"
andrewboyson 74:c3756bfa960e 8 #include "tcp.h"
andrewboyson 74:c3756bfa960e 9 #include "tcphdr.h"
andrewboyson 74:c3756bfa960e 10 #include "tcpsend.h"
andrewboyson 74:c3756bfa960e 11 #include "tcb.h"
andrewboyson 74:c3756bfa960e 12 #include "ip4.h"
andrewboyson 74:c3756bfa960e 13 #include "dhcp.h"
andrewboyson 74:c3756bfa960e 14 #include "http.h"
andrewboyson 74:c3756bfa960e 15 #include "led.h"
andrewboyson 93:580fc113d9e9 16 #include "mstimer.h"
andrewboyson 89:9b765a67699b 17
andrewboyson 89:9b765a67699b 18 static void log(void (*traceback)(void), char* fmt, ...)
andrewboyson 74:c3756bfa960e 19 {
andrewboyson 78:9d8fc88df405 20 if (TcpTrace)
andrewboyson 78:9d8fc88df405 21 {
andrewboyson 78:9d8fc88df405 22 if (NetTraceNewLine) Log("\r\n");
andrewboyson 89:9b765a67699b 23 LogTimeF("TCP port %hu - ", TcpHdrSrcPort);
andrewboyson 75:603b10404183 24 va_list argptr;
andrewboyson 75:603b10404183 25 va_start(argptr, fmt);
andrewboyson 75:603b10404183 26 LogV(fmt, argptr);
andrewboyson 75:603b10404183 27 va_end(argptr);
andrewboyson 75:603b10404183 28 Log("\r\n");
andrewboyson 75:603b10404183 29 if (NetTraceStack) traceback();
andrewboyson 75:603b10404183 30 }
andrewboyson 75:603b10404183 31 }
andrewboyson 75:603b10404183 32
andrewboyson 88:1ba13e6062a3 33 static void handleSyn(void *pPacket, int ipType, int remArIndex, int locMss, struct tcb* pTcb)
andrewboyson 74:c3756bfa960e 34 {
andrewboyson 74:c3756bfa960e 35 //Get the MSS to use for sends - it is the lower of the MSS advertised by the remote host and our local MSS
andrewboyson 74:c3756bfa960e 36 int remMss = TcpHdrMssGet();
andrewboyson 74:c3756bfa960e 37 pTcb->remMss = remMss ? remMss : 536; //default MSS for IPv4 [576 - 20(TCP) - 20(IP)];
andrewboyson 74:c3756bfa960e 38 if (pTcb->remMss > locMss) pTcb->remMss = locMss;
andrewboyson 74:c3756bfa960e 39
andrewboyson 93:580fc113d9e9 40 pTcb->timeSendsBeingAcked = MsTimerCount;
andrewboyson 82:20781198d26d 41 pTcb->countSendsNotAcked = 0;
andrewboyson 79:f50e02fb5c94 42 pTcb->rcvdFin = false;
andrewboyson 79:f50e02fb5c94 43 pTcb->sentFin = false;
andrewboyson 79:f50e02fb5c94 44 pTcb->todo = 0;
andrewboyson 79:f50e02fb5c94 45 pTcb->remIsn = TcpHdrSeqNum;
andrewboyson 79:f50e02fb5c94 46 pTcb->locIsn = TcbGetIsn();
andrewboyson 79:f50e02fb5c94 47 pTcb->bytesRcvdFromRem = 0;
andrewboyson 79:f50e02fb5c94 48 pTcb->bytesAckdByRem = 0;
andrewboyson 79:f50e02fb5c94 49 pTcb->bytesAckdToRem = 0;
andrewboyson 79:f50e02fb5c94 50 pTcb->bytesSentToRem = 0;
andrewboyson 74:c3756bfa960e 51 }
andrewboyson 88:1ba13e6062a3 52 static void handleReceivedData(void* pPacket, int dataLength, uint32_t position, struct tcb* pTcb)
andrewboyson 74:c3756bfa960e 53 {
andrewboyson 74:c3756bfa960e 54 pTcb->window = TcpHdrWindow;
andrewboyson 74:c3756bfa960e 55 char* pData = (char*)pPacket + TcpHdrSizeGet();
andrewboyson 74:c3756bfa960e 56 switch (pTcb->locPort)
andrewboyson 74:c3756bfa960e 57 {
andrewboyson 74:c3756bfa960e 58 case 80:
andrewboyson 75:603b10404183 59 HttpHandleRequest(dataLength, pData, position, &pTcb->todo);
andrewboyson 74:c3756bfa960e 60 break;
andrewboyson 74:c3756bfa960e 61 default:
andrewboyson 74:c3756bfa960e 62 break;
andrewboyson 74:c3756bfa960e 63 }
andrewboyson 74:c3756bfa960e 64 }
andrewboyson 90:955f4c6e18a9 65 static int sendResetFromPacket(int* pSizeTx, void* pPacketTx, int ipType, int remArIndex, int locIpScope, int seqLengthRcvd)
andrewboyson 89:9b765a67699b 66 {
andrewboyson 90:955f4c6e18a9 67 /*RFC793 p36 If the connection does not exist (CLOSED) then a reset is sent
andrewboyson 90:955f4c6e18a9 68 in response to any incoming segment except another reset.
andrewboyson 90:955f4c6e18a9 69 If the incoming segment has an ACK field, the reset takes its sequence number from the ACK field of the segment,
andrewboyson 90:955f4c6e18a9 70 otherwise the reset has sequence number zero
andrewboyson 90:955f4c6e18a9 71 and
andrewboyson 90:955f4c6e18a9 72 the ACK field is set to the sum of the sequence number and segment length of the incoming segment.
andrewboyson 90:955f4c6e18a9 73 The connection remains in the CLOSED state.
andrewboyson 90:955f4c6e18a9 74 In TcpSendReset TcpHdrAckNum = pTcb->bytesAckdToRem + pTcb->remIsn; //Set up the acknowledgement field ready to send
andrewboyson 90:955f4c6e18a9 75 TcpHdrSeqNum = pTcb->bytesSentToRem + pTcb->locIsn; //Set up the start of the message before adding the bytes sent
andrewboyson 90:955f4c6e18a9 76 */
andrewboyson 90:955f4c6e18a9 77
andrewboyson 89:9b765a67699b 78 struct tcb tcb;
andrewboyson 89:9b765a67699b 79 struct tcb* pTcb = &tcb;
andrewboyson 93:580fc113d9e9 80 pTcb->timeLastRcvd = MsTimerCount;
andrewboyson 89:9b765a67699b 81 pTcb->remArIndex = remArIndex;
andrewboyson 89:9b765a67699b 82 pTcb->ipType = ipType;
andrewboyson 89:9b765a67699b 83 pTcb->locIpScope = locIpScope;
andrewboyson 89:9b765a67699b 84 pTcb->remPort = TcpHdrSrcPort;
andrewboyson 89:9b765a67699b 85 pTcb->locPort = TcpHdrDstPort;
andrewboyson 89:9b765a67699b 86 pTcb->window = TcpHdrWindow;
andrewboyson 89:9b765a67699b 87 pTcb->state = TCB_EMPTY;
andrewboyson 89:9b765a67699b 88
andrewboyson 93:580fc113d9e9 89 pTcb->timeSendsBeingAcked = MsTimerCount;
andrewboyson 90:955f4c6e18a9 90 pTcb->countSendsNotAcked = 0;
andrewboyson 90:955f4c6e18a9 91 pTcb->rcvdFin = false;
andrewboyson 90:955f4c6e18a9 92 pTcb->sentFin = false;
andrewboyson 90:955f4c6e18a9 93 pTcb->todo = 0;
andrewboyson 90:955f4c6e18a9 94 pTcb->remIsn = TcpHdrSeqNum + seqLengthRcvd; //Ack number
andrewboyson 90:955f4c6e18a9 95 pTcb->locIsn = TcpHdrACK ? TcpHdrAckNum : 0; //Seq number
andrewboyson 90:955f4c6e18a9 96 pTcb->bytesRcvdFromRem = 0;
andrewboyson 90:955f4c6e18a9 97 pTcb->bytesAckdByRem = 0;
andrewboyson 90:955f4c6e18a9 98 pTcb->bytesAckdToRem = 0;
andrewboyson 90:955f4c6e18a9 99 pTcb->bytesSentToRem = 0;
andrewboyson 90:955f4c6e18a9 100
andrewboyson 89:9b765a67699b 101 return TcpSendReset(pSizeTx, pPacketTx, pTcb);
andrewboyson 89:9b765a67699b 102 }
andrewboyson 74:c3756bfa960e 103
andrewboyson 80:4ef1500fca1d 104 int TcpHandleReceivedPacket(void (*traceback)(void), int sizeRx, void* pPacketRx, int* pSizeTx, void* pPacketTx, int ipType, int remArIndex, int locIpScope)
andrewboyson 74:c3756bfa960e 105 {
andrewboyson 90:955f4c6e18a9 106 int action = DO_NOTHING;
andrewboyson 89:9b765a67699b 107 bool traceRequested = false;
andrewboyson 86:55bc5ddac16c 108
andrewboyson 86:55bc5ddac16c 109 Led1Set(true);
andrewboyson 89:9b765a67699b 110
andrewboyson 89:9b765a67699b 111 TcpHdrReadFromPacket(pPacketRx);
andrewboyson 89:9b765a67699b 112
andrewboyson 78:9d8fc88df405 113 if (remArIndex < 0)
andrewboyson 78:9d8fc88df405 114 {
andrewboyson 89:9b765a67699b 115 log(traceback, "invalid remote AR index %d -> ignored packet", remArIndex);
andrewboyson 86:55bc5ddac16c 116 Led1Set(false);
andrewboyson 78:9d8fc88df405 117 return DO_NOTHING;
andrewboyson 78:9d8fc88df405 118 }
andrewboyson 78:9d8fc88df405 119
andrewboyson 74:c3756bfa960e 120 int dataLength = sizeRx - TcpHdrSizeGet();
andrewboyson 74:c3756bfa960e 121 int locMss = *pSizeTx - TcpHdrSizeGet();
andrewboyson 74:c3756bfa960e 122
andrewboyson 90:955f4c6e18a9 123 //Calculate the sequence length of the received packet
andrewboyson 90:955f4c6e18a9 124 int seqLengthRcvd = 0;
andrewboyson 90:955f4c6e18a9 125 if (TcpHdrSYN) seqLengthRcvd += 1; //Add one to acknowledge the SYN
andrewboyson 90:955f4c6e18a9 126 seqLengthRcvd += dataLength; //Add the number of bytes received
andrewboyson 90:955f4c6e18a9 127 if (TcpHdrFIN) seqLengthRcvd += 1; //Add one to acknowledge the FIN
andrewboyson 90:955f4c6e18a9 128
andrewboyson 74:c3756bfa960e 129 //Filter out unwanted links
andrewboyson 74:c3756bfa960e 130 switch (TcpHdrDstPort)
andrewboyson 74:c3756bfa960e 131 {
andrewboyson 74:c3756bfa960e 132 case 80:
andrewboyson 74:c3756bfa960e 133 if (HttpTrace)
andrewboyson 74:c3756bfa960e 134 {
andrewboyson 74:c3756bfa960e 135 if (NetTraceNewLine) Log("\r\n");
andrewboyson 74:c3756bfa960e 136 LogTime("HTTP server request\r\n");
andrewboyson 89:9b765a67699b 137 traceRequested = true;
andrewboyson 74:c3756bfa960e 138 }
andrewboyson 74:c3756bfa960e 139 break;
andrewboyson 74:c3756bfa960e 140
andrewboyson 89:9b765a67699b 141 default: //Send reset if unknown port
andrewboyson 89:9b765a67699b 142 log(traceback, "unhandled local port %hu -> sent reset", TcpHdrDstPort);
andrewboyson 90:955f4c6e18a9 143 action = sendResetFromPacket(pSizeTx, pPacketTx, ipType, remArIndex, locIpScope, seqLengthRcvd);
andrewboyson 86:55bc5ddac16c 144 Led1Set(false);
andrewboyson 90:955f4c6e18a9 145 return action;
andrewboyson 74:c3756bfa960e 146 }
andrewboyson 74:c3756bfa960e 147
andrewboyson 76:17534bde28d3 148 //Get the Transmission Control Block
andrewboyson 88:1ba13e6062a3 149 struct tcb* pTcb = TcbGetExisting(ipType, remArIndex, locIpScope, TcpHdrSrcPort, TcpHdrDstPort);
andrewboyson 76:17534bde28d3 150 if (!pTcb) pTcb = TcbGetEmpty();
andrewboyson 89:9b765a67699b 151 if (!pTcb) //send reset if no more tcbs are available
andrewboyson 76:17534bde28d3 152 {
andrewboyson 89:9b765a67699b 153 log(traceback, "no more tcbs available -> sent reset");
andrewboyson 90:955f4c6e18a9 154 action = sendResetFromPacket(pSizeTx, pPacketTx, ipType, remArIndex, locIpScope, seqLengthRcvd);
andrewboyson 86:55bc5ddac16c 155 Led1Set(false);
andrewboyson 90:955f4c6e18a9 156 return action;
andrewboyson 76:17534bde28d3 157 }
andrewboyson 93:580fc113d9e9 158 pTcb->timeLastRcvd = MsTimerCount;
andrewboyson 76:17534bde28d3 159 pTcb->remArIndex = remArIndex;
andrewboyson 76:17534bde28d3 160 pTcb->ipType = ipType;
andrewboyson 81:50bfdd512f23 161 pTcb->locIpScope = locIpScope;
andrewboyson 76:17534bde28d3 162 pTcb->remPort = TcpHdrSrcPort;
andrewboyson 76:17534bde28d3 163 pTcb->locPort = TcpHdrDstPort;
andrewboyson 76:17534bde28d3 164 pTcb->window = TcpHdrWindow;
andrewboyson 75:603b10404183 165
andrewboyson 74:c3756bfa960e 166 //Handle request to reset
andrewboyson 74:c3756bfa960e 167 if (TcpHdrRST)
andrewboyson 74:c3756bfa960e 168 {
andrewboyson 76:17534bde28d3 169 if (pTcb->state)
andrewboyson 74:c3756bfa960e 170 {
andrewboyson 89:9b765a67699b 171 log(traceback, "received reset -> reaped TCB");
andrewboyson 75:603b10404183 172 pTcb->state = TCB_EMPTY;
andrewboyson 74:c3756bfa960e 173 }
andrewboyson 86:55bc5ddac16c 174 Led1Set(false);
andrewboyson 74:c3756bfa960e 175 return DO_NOTHING; //Don't reply
andrewboyson 74:c3756bfa960e 176 }
andrewboyson 74:c3756bfa960e 177
andrewboyson 74:c3756bfa960e 178 //Handle request to synchronise
andrewboyson 74:c3756bfa960e 179 if (TcpHdrSYN)
andrewboyson 74:c3756bfa960e 180 {
andrewboyson 76:17534bde28d3 181 if (pTcb->state)
andrewboyson 75:603b10404183 182 {
andrewboyson 89:9b765a67699b 183 log(traceback, "received a SYN on an open connection -> sent reset");
andrewboyson 75:603b10404183 184 pTcb->state = TCB_EMPTY;
andrewboyson 90:955f4c6e18a9 185 action = TcpSendReset(pSizeTx, pPacketTx, pTcb);
andrewboyson 86:55bc5ddac16c 186 Led1Set(false);
andrewboyson 90:955f4c6e18a9 187 return action;
andrewboyson 75:603b10404183 188 }
andrewboyson 76:17534bde28d3 189 else
andrewboyson 75:603b10404183 190 {
andrewboyson 88:1ba13e6062a3 191 handleSyn(pPacketRx, ipType, remArIndex, locMss, pTcb);
andrewboyson 75:603b10404183 192 }
andrewboyson 74:c3756bfa960e 193 }
andrewboyson 74:c3756bfa960e 194
andrewboyson 90:955f4c6e18a9 195 //Handle non SYN packet on an empty connection
andrewboyson 76:17534bde28d3 196 if (!TcpHdrSYN && !pTcb->state)
andrewboyson 76:17534bde28d3 197 {
andrewboyson 90:955f4c6e18a9 198
andrewboyson 89:9b765a67699b 199 log(traceback, "non SYN packet received on a closed connection -> sent reset");
andrewboyson 78:9d8fc88df405 200 pTcb->state = TCB_EMPTY;
andrewboyson 90:955f4c6e18a9 201 action = sendResetFromPacket(pSizeTx, pPacketTx, ipType, remArIndex, locIpScope, seqLengthRcvd);
andrewboyson 86:55bc5ddac16c 202 Led1Set(false);
andrewboyson 90:955f4c6e18a9 203 return action;
andrewboyson 76:17534bde28d3 204 }
andrewboyson 76:17534bde28d3 205
andrewboyson 79:f50e02fb5c94 206 //Check if the acks of bytes sent has progressed and reset the timer
andrewboyson 91:879545b19260 207 uint32_t ackRcvdFromRem = TcpHdrACK ? TcpHdrAckNum - pTcb->locIsn : 0;
andrewboyson 82:20781198d26d 208 if (ackRcvdFromRem > pTcb->bytesAckdByRem)
andrewboyson 82:20781198d26d 209 {
andrewboyson 93:580fc113d9e9 210 pTcb->timeSendsBeingAcked = MsTimerCount;
andrewboyson 82:20781198d26d 211 pTcb->countSendsNotAcked = 0;
andrewboyson 82:20781198d26d 212 }
andrewboyson 79:f50e02fb5c94 213
andrewboyson 79:f50e02fb5c94 214 //Record the number of bytes acked by the remote host
andrewboyson 79:f50e02fb5c94 215 pTcb->bytesAckdByRem = ackRcvdFromRem;
andrewboyson 79:f50e02fb5c94 216
andrewboyson 76:17534bde28d3 217 /* If the connection is in a synchronized state
andrewboyson 76:17534bde28d3 218 any unacceptable segment (out of window sequence number or
andrewboyson 76:17534bde28d3 219 unacceptible acknowledgment number) must elicit only an empty
andrewboyson 76:17534bde28d3 220 acknowledgment segment containing the current send-sequence number
andrewboyson 76:17534bde28d3 221 and an acknowledgment indicating the next sequence number expected
andrewboyson 76:17534bde28d3 222 to be received, and the connection remains in the same state.*/
andrewboyson 74:c3756bfa960e 223 uint32_t seqRcvdFromRem = TcpHdrSeqNum - pTcb->remIsn;
andrewboyson 78:9d8fc88df405 224 if (seqRcvdFromRem != pTcb->bytesAckdToRem)
andrewboyson 78:9d8fc88df405 225 {
andrewboyson 79:f50e02fb5c94 226 //Only warn non keep-alives
andrewboyson 79:f50e02fb5c94 227 if (seqRcvdFromRem != 0 || pTcb->bytesAckdToRem != 1)
andrewboyson 79:f50e02fb5c94 228 {
andrewboyson 89:9b765a67699b 229 log(traceback, "seq rcvd is %d and last seq ackd was %d -> resent last ACK", seqRcvdFromRem, pTcb->bytesAckdToRem);
andrewboyson 79:f50e02fb5c94 230 }
andrewboyson 90:955f4c6e18a9 231 action = TcpResendLastAck(pSizeTx, pPacketTx, pTcb);
andrewboyson 86:55bc5ddac16c 232 Led1Set(false);
andrewboyson 90:955f4c6e18a9 233 return action;
andrewboyson 78:9d8fc88df405 234 }
andrewboyson 90:955f4c6e18a9 235 //Ignore data before established
andrewboyson 90:955f4c6e18a9 236 if (pTcb->state != TCB_ESTABLISHED && dataLength)
andrewboyson 90:955f4c6e18a9 237 {
andrewboyson 90:955f4c6e18a9 238 log(traceback, "data received before connection established -> sent reset");
andrewboyson 90:955f4c6e18a9 239 pTcb->state = TCB_EMPTY;
andrewboyson 90:955f4c6e18a9 240 action = TcpSendReset(pSizeTx, pPacketTx, pTcb);
andrewboyson 90:955f4c6e18a9 241 Led1Set(false);
andrewboyson 90:955f4c6e18a9 242 return action;
andrewboyson 90:955f4c6e18a9 243 }
andrewboyson 90:955f4c6e18a9 244
andrewboyson 86:55bc5ddac16c 245 Led2Set(true);
andrewboyson 90:955f4c6e18a9 246
andrewboyson 74:c3756bfa960e 247 //Handle FIN
andrewboyson 74:c3756bfa960e 248 if (TcpHdrFIN) pTcb->rcvdFin = true; //When reply is all sent only a passive close is needed
andrewboyson 90:955f4c6e18a9 249
andrewboyson 90:955f4c6e18a9 250 //From now on there are no errors so display traceback if requested
andrewboyson 90:955f4c6e18a9 251 if (traceRequested && NetTraceStack) traceback();
andrewboyson 74:c3756bfa960e 252
andrewboyson 75:603b10404183 253 //Record the number of bytes received from the remote host
andrewboyson 76:17534bde28d3 254 pTcb->bytesRcvdFromRem += seqLengthRcvd;
andrewboyson 74:c3756bfa960e 255
andrewboyson 76:17534bde28d3 256 switch (pTcb->state) //This is the state of the connection BEFORE this packet arrived
andrewboyson 74:c3756bfa960e 257 {
andrewboyson 74:c3756bfa960e 258 case TCB_EMPTY:
andrewboyson 74:c3756bfa960e 259 pTcb->state = TCB_SYN_RECEIVED;
andrewboyson 74:c3756bfa960e 260 break;
andrewboyson 74:c3756bfa960e 261
andrewboyson 74:c3756bfa960e 262 case TCB_SYN_RECEIVED:
andrewboyson 74:c3756bfa960e 263 pTcb->state = TCB_ESTABLISHED;
andrewboyson 74:c3756bfa960e 264 break;
andrewboyson 74:c3756bfa960e 265
andrewboyson 74:c3756bfa960e 266 case TCB_ESTABLISHED:
andrewboyson 88:1ba13e6062a3 267 if (dataLength) handleReceivedData (pPacketRx, dataLength, seqRcvdFromRem - 1, pTcb);
andrewboyson 74:c3756bfa960e 268 if (pTcb->sentFin)
andrewboyson 74:c3756bfa960e 269 {
andrewboyson 77:6cb7d92c37f3 270 pTcb->state = pTcb->rcvdFin ? TCB_EMPTY : TCB_CLOSE_FIN_WAIT;
andrewboyson 74:c3756bfa960e 271 }
andrewboyson 74:c3756bfa960e 272 break;
andrewboyson 74:c3756bfa960e 273
andrewboyson 74:c3756bfa960e 274 case TCB_CLOSE_FIN_WAIT: //End of active close
andrewboyson 74:c3756bfa960e 275 if (TcpHdrFIN)
andrewboyson 74:c3756bfa960e 276 {
andrewboyson 74:c3756bfa960e 277 pTcb->state = TCB_EMPTY;//Ignore ACK to our FIN. Wait for FIN then close.
andrewboyson 74:c3756bfa960e 278 }
andrewboyson 74:c3756bfa960e 279 break;
andrewboyson 74:c3756bfa960e 280
andrewboyson 74:c3756bfa960e 281 }
andrewboyson 74:c3756bfa960e 282
andrewboyson 90:955f4c6e18a9 283 action = TcpSend(pSizeTx, pPacketTx, pTcb);
andrewboyson 86:55bc5ddac16c 284 Led1Set(false);
andrewboyson 86:55bc5ddac16c 285 Led2Set(false);
andrewboyson 86:55bc5ddac16c 286
andrewboyson 90:955f4c6e18a9 287 return action;
andrewboyson 74:c3756bfa960e 288 }