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bug fix: using memcpy() to append CRC checksum to odd-size payload caused memory corruption, use individual byte assignments instead

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zhitao 2008-11-25 16:05:22 +00:00
parent ae271a7f2f
commit 6b33cf434f
1 changed files with 10 additions and 8 deletions
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14
platform/msb430/dev/cc1020.c
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@ -114,7 +114,7 @@ dma_callback(void)
dma_done = 1; dma_done = 1;
} }
static static void
reset_receiver(void) reset_receiver(void)
{ {
// reset receiver // reset receiver
@ -260,8 +260,9 @@ cc1020_send(const void *buf, unsigned short len)
cc1020_txlen += len; cc1020_txlen += len;
// Send checksum // Send checksum
memcpy((char *)cc1020_txbuf + cc1020_txlen, &rxcrc, CRC_LEN); /* printf("send checksum %04hx\n", rxcrc); */
cc1020_txlen += CRC_LEN; cc1020_txbuf[cc1020_txlen++] = (uint8_t)(rxcrc >> 8);
cc1020_txbuf[cc1020_txlen++] = (uint8_t)(rxcrc & 0xFF);
// suffix // suffix
cc1020_txbuf[cc1020_txlen++] = TAIL; cc1020_txbuf[cc1020_txlen++] = TAIL;
@ -398,14 +399,13 @@ PROCESS_THREAD(cc1020_receiver_process, ev, data)
// CHECKSUM CHECK // CHECKSUM CHECK
uint16_t expected_crc = 0xffff; uint16_t expected_crc = 0xffff;
uint16_t actual_crc = -1; uint16_t actual_crc = -1;
memcpy(&actual_crc, &cc1020_rxbuf[cc1020_rxlen - CRC_LEN], CRC_LEN); actual_crc = (cc1020_rxbuf[cc1020_rxlen - CRC_LEN] << 8) | cc1020_rxbuf[cc1020_rxlen - CRC_LEN + 1];
cc1020_rxlen -= CRC_LEN; cc1020_rxlen -= CRC_LEN;
expected_crc = crc16_add((uint8_t) (cc1020_rxlen & 0xff), expected_crc); expected_crc = crc16_add((uint8_t) (cc1020_rxlen & 0xff), expected_crc);
expected_crc = crc16_add((uint8_t) ((cc1020_rxlen >> 8) & 0xff), expected_crc = crc16_add((uint8_t) ((cc1020_rxlen >> 8) & 0xff),
expected_crc); expected_crc);
int i;
int i = 0;
for(i = HDRSIZE; i < cc1020_rxlen; i++){ for(i = HDRSIZE; i < cc1020_rxlen; i++){
expected_crc = crc16_add(cc1020_rxbuf[i], expected_crc); expected_crc = crc16_add(cc1020_rxbuf[i], expected_crc);
} }
@ -415,6 +415,8 @@ PROCESS_THREAD(cc1020_receiver_process, ev, data)
} else { } else {
RIMESTATS_ADD(badcrc); RIMESTATS_ADD(badcrc);
reset_receiver(); reset_receiver();
/* printf("bad crc. expected: %04hx received: %04hx\n", */
/* expected_crc, actual_crc, cc1020_rxlen); */
} }
} }
} }