[Qemu-devel] [PATCH v4 2/9] Adding utility function net_checksum_add_cont() that allows checksum calculation of scattered data with odd chunk sizes

[Dmitry Fleytman <dmitry.fleytman@ravellosystems.com>]

Adding utility function net_raw_checksum() that calculates checksum
of buffer given

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Yan Vugenfirer <yan@daynix.com>
---
 net/checksum.c |   13 +++++++------
 net/checksum.h |   14 +++++++++++++-
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/net/checksum.c b/net/checksum.c
index 9919b2e..4fa5563 100644
--- a/net/checksum.c
+++ b/net/checksum.c
@@ -20,16 +20,17 @@
 #define PROTO_TCP  6
 #define PROTO_UDP 17
 
-uint32_t net_checksum_add(int len, uint8_t *buf)
+uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
 {
     uint32_t sum = 0;
     int i;
 
-    for (i = 0; i < len; i++) {
-	if (i & 1)
-	    sum += (uint32_t)buf[i];
-	else
-	    sum += (uint32_t)buf[i] << 8;
+    for (i = seq; i < seq + len; i++) {
+        if (i & 1) {
+            sum += (uint32_t)buf[i - seq];
+        } else {
+            sum += (uint32_t)buf[i - seq] << 8;
+        }
     }
     return sum;
 }
diff --git a/net/checksum.h b/net/checksum.h
index 1f05298..171924c 100644
--- a/net/checksum.h
+++ b/net/checksum.h
@@ -20,10 +20,22 @@
 
 #include <stdint.h>
 
-uint32_t net_checksum_add(int len, uint8_t *buf);
+uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq);
 uint16_t net_checksum_finish(uint32_t sum);
 uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
                              uint8_t *addrs, uint8_t *buf);
 void net_checksum_calculate(uint8_t *data, int length);
 
+static inline uint32_t
+net_checksum_add(int len, uint8_t *buf)
+{
+    return net_checksum_add_cont(len, buf, 0);
+}
+
+static inline uint16_t
+net_raw_checksum(uint8_t *data, int length)
+{
+  return net_checksum_finish(net_checksum_add(length, data));
+}
+
 #endif /* QEMU_NET_CHECKSUM_H */
-- 
1.7.7.6