From 1d77d032168bd495c53589cca596131a992473c4 Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Wed, 27 Jun 2012 12:02:58 +0100
Subject: [PATCH] [tcpip] Allow for architecture-specific TCP/IP checksum
 routines

Calculating the TCP/IP checksum on received packets accounts for a
substantial fraction of the response latency.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/arch/x86/include/bits/tcpip.h | 12 ++++++++++++
 src/include/ipxe/tcpip.h          | 12 ++++++++++--
 src/net/tcpip.c                   |  4 ++--
 3 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 src/arch/x86/include/bits/tcpip.h

diff --git a/src/arch/x86/include/bits/tcpip.h b/src/arch/x86/include/bits/tcpip.h
new file mode 100644
index 00000000..9ae8d920
--- /dev/null
+++ b/src/arch/x86/include/bits/tcpip.h
@@ -0,0 +1,12 @@
+#ifndef _BITS_TCPIP_H
+#define _BITS_TCPIP_H
+
+/** @file
+ *
+ * Transport-network layer interface
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#endif /* _BITS_TCPIP_H */
diff --git a/src/include/ipxe/tcpip.h b/src/include/ipxe/tcpip.h
index cdf554ea..34d7f88f 100644
--- a/src/include/ipxe/tcpip.h
+++ b/src/include/ipxe/tcpip.h
@@ -13,6 +13,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/socket.h>
 #include <ipxe/in.h>
 #include <ipxe/tables.h>
+#include <bits/tcpip.h>
 
 struct io_buffer;
 struct net_device;
@@ -121,8 +122,15 @@ extern int tcpip_tx ( struct io_buffer *iobuf, struct tcpip_protocol *tcpip,
 		      struct sockaddr_tcpip *st_dest,
 		      struct net_device *netdev,
 		      uint16_t *trans_csum );
-extern uint16_t tcpip_continue_chksum ( uint16_t partial,
-					const void *data, size_t len );
+extern uint16_t generic_tcpip_continue_chksum ( uint16_t partial,
+						const void *data, size_t len );
 extern uint16_t tcpip_chksum ( const void *data, size_t len );
 
+/* Use generic_tcpip_continue_chksum() if no architecture-specific
+ * version is available
+ */
+#ifndef tcpip_continue_chksum
+#define tcpip_continue_chksum generic_tcpip_continue_chksum
+#endif
+
 #endif /* _IPXE_TCPIP_H */
diff --git a/src/net/tcpip.c b/src/net/tcpip.c
index 4451bf11..8e187f7e 100644
--- a/src/net/tcpip.c
+++ b/src/net/tcpip.c
@@ -97,8 +97,8 @@ int tcpip_tx ( struct io_buffer *iobuf, struct tcpip_protocol *tcpip_protocol,
  * or both.  Deciding which to swap is left as an exercise for the
  * interested reader.
  */
-uint16_t tcpip_continue_chksum ( uint16_t partial, const void *data,
-				 size_t len ) {
+uint16_t generic_tcpip_continue_chksum ( uint16_t partial,
+					 const void *data, size_t len ) {
 	unsigned int cksum = ( ( ~partial ) & 0xffff );
 	unsigned int value;
 	unsigned int i;