Clean-up naming associated with network checksums

13 files changed, 247 insertions, 65 deletions

diff --git a/nuttx/net/README.txt b/nuttx/net/README.txt
index f072c0786..db1f6aa98 100644
--- a/nuttx/net/README.txt
+++ b/nuttx/net/README.txt
@@ -12,6 +12,7 @@ Directory Structure
        +- devif    - Stack/device interface layer
        +- icmp     - Internet Control Message Protocol
        +- iob      - I/O buffering logic
+       +- ipv6     - Logic unique to IPv6
        +- netdev   - Socket network device interface
        +- pkt      - "Raw" packet socket support
        +- socket   - BSD socket interface
@@ -21,18 +22,18 @@ Directory Structure
        `- utils    - Miscellaneous utility functions
 
 
-    +-------------------------------------------------------------+
-    |                   Application layer                         |
-    +-------------------------------------------------------------+
-    +-------------------------------------------------------------+
-    |                 Socket layer (socket/)                      |
-    +-------------------------------------------------------------+
-    +------------++-----------------------------------------------+
-    |  Network   ||  Protocol stacks (arp, icmp, pkt, tcp, udp)   |
-    |   Device   |+-----------------------------------------------+
-    | Interface  |+---------------------------------++------------+
-    | (netdev/)  ||Network Device Interface (devif/)|| Utilities  |
-    +------------++---------------------------------++------------+
-    +-------------------------------------------------------------+
-    |                  Network Device Drivers                     |
-    +-------------------------------------------------------------+
+    +----------------------------------------------------------------+
+    |                     Application layer                          |
+    +----------------------------------------------------------------+
+    +----------------------------------------------------------------+
+    |                   Socket layer (socket/)                       |
+    +----------------------------------------------------------------+
+    +------------++--------------------------------------------------+
+    |  Network   || Protocol stacks (arp, ipv6, icmp, pkt, tcp, udp) |
+    |   Device   |+--------------------------------------------------+
+    | Interface  |+------------------------------------++------------+
+    | (netdev/)  ||  Network Device Interface (devif/) || Utilities  |
+    +------------++------------------------------------++------------+
+    +----------------------------------------------------------------+
+    |                    Network Device Drivers                      |
+    +----------------------------------------------------------------+
diff --git a/nuttx/net/icmp/icmp_input.c b/nuttx/net/icmp/icmp_input.c
index 2958b323f..e891ccdfd 100644
--- a/nuttx/net/icmp/icmp_input.c
+++ b/nuttx/net/icmp/icmp_input.c
@@ -56,6 +56,7 @@
 
 #include "uip/uip.h"
 #include "icmp/icmp.h"
+#include "utils/utils.h"
 
 #ifdef CONFIG_NET_ICMP
 
diff --git a/nuttx/net/icmp/icmp_send.c b/nuttx/net/icmp/icmp_send.c
index 7ee1fb1fa..5f1911ad6 100644
--- a/nuttx/net/icmp/icmp_send.c
+++ b/nuttx/net/icmp/icmp_send.c
@@ -48,6 +48,7 @@
 #include <nuttx/net/netstats.h>
 
 #include "uip/uip.h"
+#include "utils/utils.h"
 #include "icmp/icmp.h"
 
 /****************************************************************************
@@ -144,7 +145,7 @@ void icmp_send(FAR struct net_driver_s *dev, FAR uip_ipaddr_t *destaddr)
       /* Calculate IP checksum. */
 
       picmp->ipchksum    = 0;
-      picmp->ipchksum    = ~(uip_ipchksum(dev));
+      picmp->ipchksum    = ~(ip_chksum(dev));
 
 #endif /* CONFIG_NET_IPv6 */
 
diff --git a/nuttx/net/igmp/igmp_input.c b/nuttx/net/igmp/igmp_input.c
index 76061bb82..856e99ada 100644
--- a/nuttx/net/igmp/igmp_input.c
+++ b/nuttx/net/igmp/igmp_input.c
@@ -133,7 +133,7 @@ void igmp_input(struct net_driver_s *dev)
 
   /* Calculate and check the IGMP checksum */
 
-  if (uip_chksum((uint16_t*)&IGMPBUF->type, UIP_IGMPH_LEN) != 0)
+  if (net_chksum((uint16_t*)&IGMPBUF->type, UIP_IGMPH_LEN) != 0)
     {
       IGMP_STATINCR(g_netstats.igmp.chksum_errors);
       nlldbg("Checksum error\n");
diff --git a/nuttx/net/igmp/igmp_send.c b/nuttx/net/igmp/igmp_send.c
index a73c16a86..8ff5ac698 100644
--- a/nuttx/net/igmp/igmp_send.c
+++ b/nuttx/net/igmp/igmp_send.c
@@ -91,7 +91,7 @@
 
 static uint16_t igmp_chksum(FAR uint8_t *buffer, int buflen)
 {
-  uint16_t sum = uip_chksum((FAR uint16_t*)buffer, buflen);
+  uint16_t sum = net_chksum((FAR uint16_t*)buffer, buflen);
   return sum ? sum : 0xffff;
 }
 
diff --git a/nuttx/net/tcp/tcp_input.c b/nuttx/net/tcp/tcp_input.c
index 909996a23..d85d1f431 100644
--- a/nuttx/net/tcp/tcp_input.c
+++ b/nuttx/net/tcp/tcp_input.c
@@ -57,6 +57,7 @@
 #include <nuttx/net/netstats.h>
 
 #include "uip/uip.h"
+#include "utils/utils.h"
 #include "tcp/tcp.h"
 
 /****************************************************************************
@@ -210,7 +211,7 @@ void tcp_input(struct net_driver_s *dev)
               goto drop;
             }
 
-          uip_incr32(conn->rcvseq, 1);
+          net_incr32(conn->rcvseq, 1);
 
           /* Parse the TCP MSS option, if present. */
 
@@ -474,7 +475,7 @@ found:
             if (dev->d_len > 0)
               {
                 flags          |= UIP_NEWDATA;
-                uip_incr32(conn->rcvseq, dev->d_len);
+                net_incr32(conn->rcvseq, dev->d_len);
               }
 
             dev->d_sndlen       = 0;
@@ -557,7 +558,7 @@ found:
             conn->tcpstateflags = UIP_ESTABLISHED;
             memcpy(conn->rcvseq, pbuf->seqno, 4);
 
-            uip_incr32(conn->rcvseq, 1);
+            net_incr32(conn->rcvseq, 1);
             conn->unacked       = 0;
 
 #ifdef CONFIG_NET_TCP_WRITE_BUFFERS
@@ -623,7 +624,7 @@ found:
              * been closed.
              */
 
-            uip_incr32(conn->rcvseq, dev->d_len + 1);
+            net_incr32(conn->rcvseq, dev->d_len + 1);
             flags |= UIP_CLOSE;
 
             if (dev->d_len > 0)
@@ -657,7 +658,7 @@ found:
                 dev->d_urglen = dev->d_len;
               }
 
-            uip_incr32(conn->rcvseq, dev->d_urglen);
+            net_incr32(conn->rcvseq, dev->d_urglen);
             dev->d_len     -= dev->d_urglen;
             dev->d_urgdata  = dev->d_appdata;
             dev->d_appdata += dev->d_urglen;
@@ -724,7 +725,7 @@ found:
               {
                 /* Update the sequence number using the saved length */
 
-                uip_incr32(conn->rcvseq, len);
+                net_incr32(conn->rcvseq, len);
               }
 
             /* Send the response, ACKing the data or not, as appropriate */
@@ -757,7 +758,7 @@ found:
 
         if (dev->d_len > 0)
           {
-            uip_incr32(conn->rcvseq, dev->d_len);
+            net_incr32(conn->rcvseq, dev->d_len);
           }
 
         if ((pbuf->flags & TCP_FIN) != 0)
@@ -775,7 +776,7 @@ found:
                 nllvdbg("TCP state: UIP_CLOSING\n");
               }
 
-            uip_incr32(conn->rcvseq, 1);
+            net_incr32(conn->rcvseq, 1);
             (void)tcp_callback(dev, conn, UIP_CLOSE);
             tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
             return;
@@ -799,7 +800,7 @@ found:
       case UIP_FIN_WAIT_2:
         if (dev->d_len > 0)
           {
-            uip_incr32(conn->rcvseq, dev->d_len);
+            net_incr32(conn->rcvseq, dev->d_len);
           }
 
         if ((pbuf->flags & TCP_FIN) != 0)
@@ -808,7 +809,7 @@ found:
             conn->timer         = 0;
             nllvdbg("TCP state: UIP_TIME_WAIT\n");
 
-            uip_incr32(conn->rcvseq, 1);
+            net_incr32(conn->rcvseq, 1);
             (void)tcp_callback(dev, conn, UIP_CLOSE);
             tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
             return;
diff --git a/nuttx/net/tcp/tcp_send.c b/nuttx/net/tcp/tcp_send.c
index f404e9d59..ddc6a3e46 100644
--- a/nuttx/net/tcp/tcp_send.c
+++ b/nuttx/net/tcp/tcp_send.c
@@ -54,6 +54,7 @@
 #include <nuttx/net/netstats.h>
 
 #include "uip/uip.h"
+#include "utils/utils.h"
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -139,7 +140,7 @@ static void tcp_sendcomplete(FAR struct net_driver_s *dev)
   /* Calculate IP checksum. */
 
   pbuf->ipchksum    = 0;
-  pbuf->ipchksum    = ~(uip_ipchksum(dev));
+  pbuf->ipchksum    = ~(ip_chksum(dev));
 
 #endif /* CONFIG_NET_IPv6 */
 
diff --git a/nuttx/net/udp/udp_input.c b/nuttx/net/udp/udp_input.c
index 43408f4cf..d2b8b1307 100644
--- a/nuttx/net/udp/udp_input.c
+++ b/nuttx/net/udp/udp_input.c
@@ -54,6 +54,7 @@
 #include <nuttx/net/netstats.h>
 
 #include "uip/uip.h"
+#include "utils/utils.h"
 #include "udp/udp.h"
 
 /****************************************************************************
diff --git a/nuttx/net/udp/udp_send.c b/nuttx/net/udp/udp_send.c
index db9b74dd6..431f06e16 100644
--- a/nuttx/net/udp/udp_send.c
+++ b/nuttx/net/udp/udp_send.c
@@ -53,6 +53,7 @@
 #include <nuttx/net/netstats.h>
 
 #include "uip/uip.h"
+#include "utils/utils.h"
 #include "udp/udp.h"
 
 /****************************************************************************
@@ -144,7 +145,7 @@ void udp_send(struct net_driver_s *dev, struct udp_conn_s *conn)
       /* Calculate IP checksum. */
 
       pudpbuf->ipchksum    = 0;
-      pudpbuf->ipchksum    = ~(uip_ipchksum(dev));
+      pudpbuf->ipchksum    = ~(ip_chksum(dev));
 
 #endif /* CONFIG_NET_IPv6 */
 
diff --git a/nuttx/net/uip/uip_input.c b/nuttx/net/uip/uip_input.c
index eaddac9bf..190b3647c 100644
--- a/nuttx/net/uip/uip_input.c
+++ b/nuttx/net/uip/uip_input.c
@@ -107,8 +107,8 @@
 
 /* Macros. */
 
-#define BUF     ((struct uip_ip_hdr *)&dev->d_buf[UIP_LLH_LEN])
-#define FBUF    ((struct uip_ip_hdr *)&uip_reassbuf[0])
+#define BUF     ((FAR struct net_iphdr_s *)&dev->d_buf[UIP_LLH_LEN])
+#define FBUF    ((FAR struct net_iphdr_s *)&uip_reassbuf[0])
 
 /* IP fragment re-assembly */
 
@@ -149,8 +149,8 @@ static uint8_t uip_reassflags;
 #if UIP_REASSEMBLY && !defined(CONFIG_NET_IPv6)
 static uint8_t uip_reass(void)
 {
-  struct uip_ip_hdr *pbuf  = BUF;
-  struct uip_ip_hdr *pfbuf = FBUF;
+  FAR struct net_iphdr_s *pbuf  = BUF;
+  FAR struct net_iphdr_s *pfbuf = FBUF;
   uint16_t offset;
   uint16_t len;
   uint16_t i;
@@ -277,7 +277,7 @@ static uint8_t uip_reass(void)
         pbuf->len[0] = uip_reasslen >> 8;
         pbuf->len[1] = uip_reasslen & 0xff;
         pbuf->ipchksum = 0;
-        pbuf->ipchksum = ~(uip_ipchksum(dev));
+        pbuf->ipchksum = ~(ip_chksum(dev));
 
         return uip_reasslen;
       }
@@ -307,9 +307,9 @@ nullreturn:
  *
  ****************************************************************************/
 
-int uip_input(struct net_driver_s *dev)
+int uip_input(FAR struct net_driver_s *dev)
 {
-  struct uip_ip_hdr *pbuf = BUF;
+  FAR struct net_iphdr_s *pbuf = BUF;
   uint16_t iplen;
 
   /* This is where the input processing starts. */
@@ -491,7 +491,7 @@ int uip_input(struct net_driver_s *dev)
     }
 
 #ifndef CONFIG_NET_IPv6
-  if (uip_ipchksum(dev) != 0xffff)
+  if (ip_chksum(dev) != 0xffff)
     {
       /* Compute and check the IP header checksum. */
 
diff --git a/nuttx/net/utils/Kconfig b/nuttx/net/utils/Kconfig
index ae2bf3130..412ece03e 100644
--- a/nuttx/net/utils/Kconfig
+++ b/nuttx/net/utils/Kconfig
@@ -2,3 +2,24 @@
 # For a description of the syntax of this configuration file,
 # see misc/tools/kconfig-language.txt.
 #
+
+config NET_ARCH_INCR32
+	bool "Architecture-specific net_incr32()"
+	default n
+	---help---
+		Define if you architecture provided an optimized version of
+		net_incr32() with prototype:
+
+			void net_incr32(FAR uint8_t *op32, uint16_t op16)
+
+config NET_ARCH_CHKSUM
+	bool "Architecture-specific net_chksum()"
+	default n
+	---help---
+		Define if you architecture provided an optimized version of
+		functions with the following prototypes:
+
+			uint16_t net_chksum(FAR uint16_t *data, uint16_t len)
+			uint16_t ip_chksum(FAR struct net_driver_s *dev)
+			uint16_t tcp_chksum(FAR struct net_driver_s *dev);
+			uint16_t udp_chksum(FAR struct net_driver_s *dev);
diff --git a/nuttx/net/utils/net_chksum.c b/nuttx/net/utils/net_chksum.c
index c6e93873f..ff8438678 100644
--- a/nuttx/net/utils/net_chksum.c
+++ b/nuttx/net/utils/net_chksum.c
@@ -54,7 +54,7 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-#define BUF ((struct uip_ip_hdr *)&dev->d_buf[UIP_LLH_LEN])
+#define BUF ((struct net_iphdr_s *)&dev->d_buf[UIP_LLH_LEN])
 #define ICMPBUF ((struct icmp_iphdr_s *)&dev->d_buf[UIP_LLH_LEN])
 
 /****************************************************************************
@@ -65,7 +65,11 @@
  * Private Functions
  ****************************************************************************/
 
-#if !UIP_ARCH_CHKSUM
+/****************************************************************************
+ * Name: chksum
+ ****************************************************************************/
+
+#if !CONFIG_NET_ARCH_CHKSUM
 static uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len)
 {
   uint16_t t;
@@ -103,10 +107,16 @@ static uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len)
 
   return sum;
 }
+#endif /* CONFIG_NET_ARCH_CHKSUM */
+
+/****************************************************************************
+ * Name: upper_layer_chksum
+ ****************************************************************************/
 
+#if !CONFIG_NET_ARCH_CHKSUM
 static uint16_t upper_layer_chksum(FAR struct net_driver_s *dev, uint8_t proto)
 {
-  struct uip_ip_hdr *pbuf = BUF;
+  FAR struct net_iphdr_s *pbuf = BUF;
   uint16_t upper_layer_len;
   uint16_t sum;
 
@@ -132,20 +142,31 @@ static uint16_t upper_layer_chksum(FAR struct net_driver_s *dev, uint8_t proto)
 
   return (sum == 0) ? 0xffff : htons(sum);
 }
+#endif /* CONFIG_NET_ARCH_CHKSUM */
 
+/****************************************************************************
+ * Name: icmp_6chksum
+ ****************************************************************************/
+
+#if !CONFIG_NET_ARCH_CHKSUM
 #ifdef CONFIG_NET_IPv6
 static uint16_t icmp_6chksum(FAR struct net_driver_s *dev)
 {
   return upper_layer_chksum(dev, UIP_PROTO_ICMP6);
 }
 #endif /* CONFIG_NET_IPv6 */
+#endif /* CONFIG_NET_ARCH_CHKSUM */
 
-#endif /* UIP_ARCH_CHKSUM */
-
-/* Calculate the Internet checksum over a buffer. */
+/****************************************************************************
+ * Name: net_carry32
+ *
+ * Description:
+ *   Calculate the Internet checksum over a buffer.
+ *
+ ****************************************************************************/
 
-#if !UIP_ARCH_ADD32
-static inline void uip_carry32(FAR uint8_t *sum, uint16_t op16)
+#if !CONFIG_NET_ARCH_INCR32
+static inline void net_carry32(FAR uint8_t *sum, uint16_t op16)
 {
   if (sum[2] < (op16 >> 8))
     {
@@ -169,64 +190,154 @@ static inline void uip_carry32(FAR uint8_t *sum, uint16_t op16)
         }
     }
 }
-#endif /* UIP_ARCH_ADD32 */
+#endif /* CONFIG_NET_ARCH_INCR32 */
 
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
 
-#if !UIP_ARCH_ADD32
-void uip_incr32(FAR uint8_t *op32, uint16_t op16)
+/****************************************************************************
+ * Name: net_incr32
+ *
+ * Description:
+ *
+ *   Carry out a 32-bit addition.
+ *
+ *   By defining CONFIG_NET_ARCH_INCR32, the architecture can replace
+ *   net_incr32 with hardware assisted solutions.
+ *
+ * Input Parameters:
+ *   op32 - A pointer to a 4-byte array representing a 32-bit integer in
+ *          network byte order (big endian).  This value may not be word
+ *          aligned. The value pointed to by op32 is modified in place
+ *
+ *   op16 - A 16-bit integer in host byte order.
+ *
+ ****************************************************************************/
+
+#if !CONFIG_NET_ARCH_INCR32
+void net_incr32(FAR uint8_t *op32, uint16_t op16)
 {
   op32[3] += (op16 & 0xff);
   op32[2] += (op16 >> 8);
-  uip_carry32(op32, op16);
+  net_carry32(op32, op16);
 }
-#endif /* UIP_ARCH_ADD32 */
+#endif /* CONFIG_NET_ARCH_INCR32 */
 
-#if !UIP_ARCH_CHKSUM
-uint16_t uip_chksum(FAR uint16_t *data, uint16_t len)
+/****************************************************************************
+ * Name: net_chksum
+ *
+ * Description:
+ *   Calculate the Internet checksum over a buffer.
+ *
+ *   The Internet checksum is the one's complement of the one's complement
+ *   sum of all 16-bit words in the buffer.
+ *
+ *   See RFC1071.
+ *
+ *   If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
+ *   provided by architecture-specific logic.
+ *
+ * Input Parameters:
+ *
+ *   buf - A pointer to the buffer over which the checksum is to be computed.
+ *
+ *   len - The length of the buffer over which the checksum is to be computed.
+ *
+ * Returned Value:
+ *   The Internet checksum of the buffer.
+ *
+ ****************************************************************************/
+
+#if !CONFIG_NET_ARCH_CHKSUM
+uint16_t net_chksum(FAR uint16_t *data, uint16_t len)
 {
   return htons(chksum(0, (uint8_t *)data, len));
 }
+#endif /* CONFIG_NET_ARCH_CHKSUM */
 
-/* Calculate the IP header checksum of the packet header in d_buf. */
+/****************************************************************************
+ * Name: ip_chksum
+ *
+ * Description:
+ *   Calculate the IP header checksum of the packet header in d_buf.
+ *
+ *   The IP header checksum is the Internet checksum of the 20 bytes of
+ *   the IP header.
+ *
+ *   If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
+ *   provided by architecture-specific logic.
+ *
+ * Returned Value:
+ *   The IP header checksum of the IP header in the d_buf buffer.
+ *
+ ****************************************************************************/
 
-#ifndef UIP_ARCH_IPCHKSUM
-uint16_t uip_ipchksum(FAR struct net_driver_s *dev)
+#if !CONFIG_NET_ARCH_CHKSUM
+uint16_t ip_chksum(FAR struct net_driver_s *dev)
 {
   uint16_t sum;
 
   sum = chksum(0, &dev->d_buf[UIP_LLH_LEN], UIP_IPH_LEN);
   return (sum == 0) ? 0xffff : htons(sum);
 }
-#endif
+#endif /* CONFIG_NET_ARCH_CHKSUM */
 
-/* Calculate the TCP checksum of the packet in d_buf and d_appdata. */
+/****************************************************************************
+ * Name: tcp_chksum
+ *
+ * Description:
+ *   Calculate the TCP checksum of the packet in d_buf and d_appdata.
+ *
+ *   The TCP checksum is the Internet checksum of data contents of the
+ *   TCP segment, and a pseudo-header as defined in RFC793.
+ *
+ *   Note: The d_appdata pointer that points to the packet data may
+ *   point anywhere in memory, so it is not possible to simply calculate
+ *   the Internet checksum of the contents of the d_buf buffer.
+ *
+ * Returned Value:
+ *   The TCP checksum of the TCP segment in d_buf and pointed to by
+ *   d_appdata.
+ *
+ ****************************************************************************/
 
+#if !CONFIG_NET_ARCH_CHKSUM
 uint16_t tcp_chksum(FAR struct net_driver_s *dev)
 {
   return upper_layer_chksum(dev, UIP_PROTO_TCP);
 }
+#endif /* CONFIG_NET_ARCH_CHKSUM */
 
-/* Calculate the UDP checksum of the packet in d_buf and d_appdata. */
+/****************************************************************************
+ * Name: udp_chksum
+ *
+ * Description:
+ *   Calculate the UDP checksum of the packet in d_buf and d_appdata.
+ *
+ ****************************************************************************/
 
-#ifdef CONFIG_NET_UDP_CHECKSUMS
+#if defined(CONFIG_NET_UDP_CHECKSUMS) && !defined(CONFIG_NET_ARCH_CHKSUM)
 uint16_t udp_chksum(FAR struct net_driver_s *dev)
 {
   return upper_layer_chksum(dev, UIP_PROTO_UDP);
 }
-#endif
+#endif /* CONFIG_NET_UDP_CHECKSUMS && !CONFIG_NET_ARCH_CHKSUM */
 
-/* Calculate the checksum of the ICMP message */
+/****************************************************************************
+ * Name: icmp_chksum
+ *
+ * Description:
+ *   Calculate the checksum of the ICMP message
+ *
+ ****************************************************************************/
 
 #if defined(CONFIG_NET_ICMP) && defined(CONFIG_NET_ICMP_PING)
 uint16_t icmp_chksum(FAR struct net_driver_s *dev, int len)
 {
   FAR struct icmp_iphdr_s *picmp = ICMPBUF;
-  return uip_chksum((uint16_t*)&picmp->type, len);
+  return net_chksum((uint16_t*)&picmp->type, len);
 }
-#endif
+#endif /* CONFIG_NET_ICMP && CONFIG_NET_ICMP_PING */
 
-#endif /* UIP_ARCH_CHKSUM */
 #endif /* CONFIG_NET */
diff --git a/nuttx/net/utils/utils.h b/nuttx/net/utils/utils.h
index 10c386edf..1ccd0aedc 100644
--- a/nuttx/net/utils/utils.h
+++ b/nuttx/net/utils/utils.h
@@ -87,6 +87,49 @@ extern "C"
 struct timeval;
 void net_dsec2timeval(uint16_t dsec, FAR struct timeval *tv);
 
+/****************************************************************************
+ * Name: tcp_chksum
+ *
+ * Description:
+ *   Calculate the TCP checksum of the packet in d_buf and d_appdata.
+ *
+ *   The TCP checksum is the Internet checksum of data contents of the
+ *   TCP segment, and a pseudo-header as defined in RFC793.
+ *
+ *   Note: The d_appdata pointer that points to the packet data may
+ *   point anywhere in memory, so it is not possible to simply calculate
+ *   the Internet checksum of the contents of the d_buf buffer.
+ *
+ * Returned Value:
+ *   The TCP checksum of the TCP segment in d_buf and pointed to by
+ *   d_appdata.
+ *
+ ****************************************************************************/
+
+uint16_t tcp_chksum(FAR struct net_driver_s *dev);
+
+/****************************************************************************
+ * Name: udp_chksum
+ *
+ * Description:
+ *   Calculate the UDP checksum of the packet in d_buf and d_appdata.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_UDP_CHECKSUMS
+uint16_t udp_chksum(FAR struct net_driver_s *dev);
+#endif
+
+/****************************************************************************
+ * Name: icmp_chksum
+ *
+ * Description:
+ *   Calculate the checksum of the ICMP message
+ *
+ ****************************************************************************/
+
+uint16_t icmp_chksum(FAR struct net_driver_s *dev, int len);
+
 #undef EXTERN
 #ifdef __cplusplus
 }