Correct a buffer size error in the STM32 ethernet driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4403 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -2468,4 +2468,8 @@
 	  this is little more than a "skeleton" file.
 	* Various files:  CAN ISO-11783 support contributed by Gary Teravskis.
 	* net/recv.c and net/recvfrom.c: Correct a bug in return value:  The the peer
-	  gracefully closes the connections, needs to return zero and not ENOTCONN
+	  gracefully closes the connections, needs to return zero and not ENOTCONN.
+	* arch/arm/src/stm32/stm32_eth.c:  Fix an error in the STM32 ethernet driver.
+	  The received buffer size must be two bytes larger to account for the two byte
+	  checksum that is appended to the packet.  Otherwise, the last two bytes of
+	  real data in the packet will get clobbered.

arch/arm/src/stm32/stm32_eth.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/stm32/stm32_eth.c
  *
- *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -140,21 +140,27 @@
 #undef CONFIG_STM32_ETH_ENHANCEDDESC
 #undef CONFIG_STM32_ETH_HWCHECKSUM
 
-/* Ethernet buffer sizes, nubmer of buffers, and number of descriptors */
+/* Ethernet buffer sizes, number of buffers, and number of descriptors */
 
 #ifndef CONFIG_NET_MULTIBUFFER
 #  error "CONFIG_NET_MULTIBUFFER is required"
 #endif
 
+/* Add 4 to the configured buffer size to account for the 2 byte checksum
+ * memory needed at the end of the maximum size packet.
+ */
+
+#define OPTIMAL_ETH_BUFSIZE (CONFIG_NET_BUFSIZE+4)
+
 #ifndef CONFIG_STM32_ETH_BUFSIZE
-#  define CONFIG_STM32_ETH_BUFSIZE CONFIG_NET_BUFSIZE
+#  define CONFIG_STM32_ETH_BUFSIZE OPTIMAL_ETH_BUFSIZE
 #endif
 
 #if CONFIG_STM32_ETH_BUFSIZE > ETH_TDES1_TBS1_MASK
 #  error "CONFIG_STM32_ETH_BUFSIZE is too large"
 #endif
 
-#if CONFIG_STM32_ETH_BUFSIZE != CONFIG_NET_BUFSIZE
+#if CONFIG_STM32_ETH_BUFSIZE != OPTIMAL_ETH_BUFSIZE
 #  warning "You using an incomplete/untested configuration"
 #endif
 
@@ -872,11 +878,11 @@ static int stm32_transmit(FAR struct stm32_ethmac_s *priv)
   struct eth_txdesc_s *txdesc;
   struct eth_txdesc_s *txfirst;
 
-  /* The internal uIP buffer size may be configured to be larger than the
+  /* The internal (optimal) uIP buffer size may be configured to be larger
-   * Ethernet buffer size.
+   * than the Ethernet buffer size.
    */
 
-#if CONFIG_NET_BUFSIZE > CONFIG_STM32_ETH_BUFSIZE
+#if OPTIMAL_ETH_BUFSIZE > CONFIG_STM32_ETH_BUFSIZE
   uint8_t *buffer;
   int bufcount;
   int lastsize;
@@ -900,7 +906,7 @@ static int stm32_transmit(FAR struct stm32_ethmac_s *priv)
 
   DEBUGASSERT(priv->dev.d_len > 0 && priv->dev.d_buf != NULL);
 
-#if CONFIG_NET_BUFSIZE > CONFIG_STM32_ETH_BUFSIZE
+#if OPTIMAL_ETH_BUFSIZE > CONFIG_STM32_ETH_BUFSIZE
   if (priv->dev.d_len > CONFIG_STM32_ETH_BUFSIZE)
     {
       /* Yes... how many buffers will be need to send the packet? */
@@ -1369,7 +1375,7 @@ static int stm32_recvframe(FAR struct stm32_ethmac_s *priv)
    *   3) All of the TX descriptors are in flight.
    *
    * This last case is obscure.  It is due to that fact that each packet
-   * that we receive can generate and unstoppable transmisson.  So we have
+   * that we receive can generate an unstoppable transmisson.  So we have
    * to stop receiving when we can not longer transmit.  In this case, the
    * transmit logic should also have disabled further RX interrupts.
    */

net/net_timeo.c

@@ -1,8 +1,8 @@
 /****************************************************************************
  * net/net_timeo.c
  *
- *   Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions

net/uip/uip_chksum.c

@@ -1,8 +1,8 @@
 /****************************************************************************
  * net/uip/uip_chksum.c
  *
- *   Copyright (C) 2007-2010 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2010, 2012 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions

net/uip/uip_input.c

@@ -2,8 +2,8 @@
  * net/uip/uip_input.c
  * The uIP TCP/IP stack code.
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Adapted for NuttX from logic in uIP which also has a BSD-like license:
  *
@@ -297,6 +297,7 @@ nullreturn:
 void uip_input(struct uip_driver_s *dev)
 {
   struct uip_ip_hdr *pbuf = BUF;
+  uint16_t iplen;
 
   /* This is where the input processing starts. */
 
@@ -343,20 +344,23 @@ void uip_input(struct uip_driver_s *dev)
    * we set d_len to the correct value.
    */
 
-  if ((pbuf->len[0] << 8) + pbuf->len[1] <= dev->d_len)
-    {
-      dev->d_len = (pbuf->len[0] << 8) + pbuf->len[1];
 #ifdef CONFIG_NET_IPv6
-      /* The length reported in the IPv6 header is the length of the
+  /* The length reported in the IPv6 header is the length of the payload
-       * payload that follows the header. However, uIP uses the d_len
+   * that follows the header. However, uIP uses the d_len variable for
-       * variable for holding the size of the entire packet, including the
+   * holding the size of the entire packet, including the IP header. For
-       * IP header. For IPv4 this is not a problem as the length field in
+   * IPv4 this is not a problem as the length field in the IPv4 header
-       * the IPv4 header contains the length of the entire packet. But
+   * contains the length of the entire packet. But for IPv6 we need to add
-       * for IPv6 we need to add the size of the IPv6 header (40 bytes).
+   * the size of the IPv6 header (40 bytes).
-       */
+   */
 
-      dev->d_len += 40;
+  iplen = (pbuf->len[0] << 8) + pbuf->len[1] + UIP_IPH_LEN;
+#else
+  iplen = (pbuf->len[0] << 8) + pbuf->len[1];
 #endif /* CONFIG_NET_IPv6 */
+
+  if (iplen <= dev->d_len)
+    {
+      dev->d_len = iplen;
     }
   else
     {
@@ -538,4 +542,3 @@ drop:
   dev->d_len = 0;
 }
 #endif /* CONFIG_NET */
-