Fix calculation of checksum on outgoing ping responses

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1617 42af7a65-404d-4744-a932-0658087f49c3

3 files changed, 15 insertions, 13 deletions

diff --git a/nuttx/net/uip/uip_chksum.c b/nuttx/net/uip/uip_chksum.c
index defb5b479..45e8894b3 100644
--- a/nuttx/net/uip/uip_chksum.c
+++ b/nuttx/net/uip/uip_chksum.c
@@ -229,11 +229,11 @@ uint16 uip_udpchksum(struct uip_driver_s *dev)
 
 /* Calculate the checksum of the ICMP message */
 
-#if defined(CONFIG_NET_ICMP) && defined(CONFIG_NET_ICMP_PING)
-uint16 uip_icmpchksum(struct uip_driver_s *dev)
+#if defined(CONFIG_NET_ICMP)
+uint16 uip_icmpchksum(struct uip_driver_s *dev, int len)
 {
   struct uip_icmpip_hdr *picmp = ICMPBUF;
-  return uip_chksum((uint16*)&picmp->type, dev->d_sndlen);
+  return uip_chksum((uint16*)&picmp->type, len);
 }
 #endif
 
diff --git a/nuttx/net/uip/uip_icmpinput.c b/nuttx/net/uip/uip_icmpinput.c
index 52352c700..f2edcbcb5 100644
--- a/nuttx/net/uip/uip_icmpinput.c
+++ b/nuttx/net/uip/uip_icmpinput.c
@@ -131,22 +131,24 @@ void uip_icmpinput(struct uip_driver_s *dev)
         }
 #endif
 
-      picmp->type = ICMP_ECHO_REPLY;
+      /* Change the ICMP type */
 
-      if (picmp->icmpchksum >= HTONS(0xffff - (ICMP_ECHO_REPLY << 8)))
-        {
-          picmp->icmpchksum += HTONS(ICMP_ECHO_REPLY << 8) + 1;
-        }
-      else
-        {
-          picmp->icmpchksum += HTONS(ICMP_ECHO_REPLY << 8);
-        }
+      picmp->type = ICMP_ECHO_REPLY;
 
       /* Swap IP addresses. */
 
       uiphdr_ipaddr_copy(picmp->destipaddr, picmp->srcipaddr);
       uiphdr_ipaddr_copy(picmp->srcipaddr, &dev->d_ipaddr);
 
+      /* Recalculate the ICMP checksum */
+
+      picmp->icmpchksum = 0;
+      picmp->icmpchksum = ~uip_icmpchksum(dev, (((uint16)picmp->len[0] << 8) | (uint16)picmp->len[1]) - UIP_IPH_LEN);
+      if (picmp->icmpchksum == 0)
+        {
+          picmp->icmpchksum = 0xffff;
+        }
+
       nvdbg("Outgoing ICMP packet length: %d (%d)\n",
             dev->d_len, (picmp->len[0] << 8) | picmp->len[1]);
 
diff --git a/nuttx/net/uip/uip_icmpsend.c b/nuttx/net/uip/uip_icmpsend.c
index 6acbf3176..0c3784e95 100644
--- a/nuttx/net/uip/uip_icmpsend.c
+++ b/nuttx/net/uip/uip_icmpsend.c
@@ -150,7 +150,7 @@ void uip_icmpsend(struct uip_driver_s *dev, uip_ipaddr_t *destaddr)
       /* Calculate the ICMP checksum. */
 
       picmp->icmpchksum  = 0;
-      picmp->icmpchksum  = ~(uip_icmpchksum(dev));
+      picmp->icmpchksum  = ~(uip_icmpchksum(dev, dev->d_sndlen));
       if (picmp->icmpchksum == 0)
         {
           picmp->icmpchksum = 0xffff;