commit 3952d80d057eb3c8c63c4661489581405cf0c87c
author Thomas Tsou <tom@tsou.cc> Tue Oct 15 15:12:24 2013 -0400
committer Thomas Tsou <tom@tsou.cc> Fri Oct 18 13:10:18 2013 -0400
tree c934a68951a37ac0cc8b58eb327961205699da51
parent fe269fe31dc2ae4bc3012d0b83ebc43edfd18cb5

Transceiver52M: Reduce and place bounds checking on I/O buffers

Previous send and receive buffers at the radio interface were
arbitrarily set to a sufficient size. For normal (non-resampling)
devices, use a block (chunk) size of 625 samples. For 64 or 100
MHz resampling devices, use 4 times the reduced resampling
numerator or denominator and provide bounds checking where
appropriate.

Signed-off-by: Thomas Tsou <tom@tsou.cc>

Transceiver52M/radioInterface.cpp

diff --git a/Transceiver52M/radioInterface.cpp b/Transceiver52M/radioInterface.cpp
index a633738..a8a54a5 100644
--- a/Transceiver52M/radioInterface.cpp
+++ b/Transceiver52M/radioInterface.cpp
@@ -30,8 +30,8 @@
 #include "convert.h"
 }
 
-#define INCHUNK		(625 * SAMPSPERSYM)
-#define OUTCHUNK	(625 * SAMPSPERSYM)
+#define CHUNK		625
+#define NUMCHUNKS	4
 
 RadioInterface::RadioInterface(RadioDevice *wRadio,
 			       int wReceiveOffset,
@@ -58,11 +58,11 @@
 
   close();
 
-  sendBuffer = new signalVector(OUTCHUNK * 20);
-  recvBuffer = new signalVector(INCHUNK * 20);
+  sendBuffer = new signalVector(CHUNK * mSPSTx);
+  recvBuffer = new signalVector(NUMCHUNKS * CHUNK * mSPSRx);
 
-  convertSendBuffer = new short[OUTCHUNK * 2 * 20];
-  convertRecvBuffer = new short[OUTCHUNK * 2 * 2];
+  convertSendBuffer = new short[sendBuffer->size() * 2];
+  convertRecvBuffer = new short[recvBuffer->size() * 2];
 
   sendCursor = 0;
   recvCursor = 0;
@@ -276,23 +276,26 @@
 void RadioInterface::pullBuffer()
 {
   bool local_underrun;
-  int num_recv, len = OUTCHUNK / mSPSTx;
+  int num_recv;
   float *output;
 
+  if (recvCursor > recvBuffer->size() - CHUNK)
+    return;
+
   /* Outer buffer access size is fixed */
   num_recv = mRadio->readSamples(convertRecvBuffer,
-                                 len,
+                                 CHUNK,
                                  &overrun,
                                  readTimestamp,
                                  &local_underrun);
-  if (num_recv != len) {
+  if (num_recv != CHUNK) {
           LOG(ALERT) << "Receive error " << num_recv;
           return;
   }
 
   output = (float *) (recvBuffer->begin() + recvCursor);
 
-  convert_short_float(output, convertRecvBuffer, 2 * len);
+  convert_short_float(output, convertRecvBuffer, 2 * num_recv);
 
   underrun |= local_underrun;
 
@@ -305,9 +308,12 @@
 {
   int num_sent;
 
-  if (sendCursor < INCHUNK)
+  if (sendCursor < CHUNK)
     return;
 
+  if (sendCursor > sendBuffer->size())
+    LOG(ALERT) << "Send buffer overflow";
+
   convert_float_short(convertSendBuffer,
                       (float *) sendBuffer->begin(),
                       powerScaling, 2 * sendCursor);