[Spice-devel] [master PATCH 2/2] server: netstat: send random data not zeros

[Uri Lublin]

WAN accelerators may compress the zeros which results with a
wrong bandwidth calculation.

The buffer is initialized once.
---
 server/main_channel.c |   32 ++++++++++++++++++++++++++++----
 1 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/server/main_channel.c b/server/main_channel.c
index a4db724..3a94066 100644
--- a/server/main_channel.c
+++ b/server/main_channel.c
@@ -34,6 +34,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>
+#include <stdlib.h>

 #include "server/red_common.h"
 #include "server/demarshallers.h"
@@ -44,7 +45,7 @@
 #include "red_channel.h"
 #include "generated_marshallers.h"

-#define ZERO_BUF_SIZE 4096
+#define RANDOM_BUF_SIZE 4096

 // approximate max receive message size for main channel
 #define RECEIVE_BUF_SIZE \
@@ -57,7 +58,7 @@

 #define PING_INTERVAL (1000 * 10)

-static uint8_t zero_page[ZERO_BUF_SIZE] = {0};
+static uint8_t random_page[RANDOM_BUF_SIZE];

 typedef struct RedsOutItem RedsOutItem;
 struct RedsOutItem {
@@ -155,6 +156,28 @@ enum NetTestStage {
     NET_TEST_STAGE_RATE,
 };

+
+static void random_page_init(void)
+{
+    static int done = 0; /* do it only once */
+    int i, n;
+    uint32_t *p = (uint32_t*)random_page;
+
+    if (done)
+        return;
+    done = 1;
+
+    /* assuming devides with no remainder. otherwise some zeros at the end */
+    n = sizeof(random_page) / sizeof(uint32_t);
+
+    srandom(time(NULL));
+    for (i=0; i<n; i++, p++) {
+        *p = random();
+    }
+
+}
+
+
 int main_channel_is_connected(MainChannel *main_chan)
 {
     return red_channel_is_connected(&main_chan->base);
@@ -370,9 +393,9 @@ static void main_channel_marshall_ping(SpiceMarshaller *m, int size, int ping_id
     spice_marshall_msg_ping(m, &ping);

     while (size > 0) {
-        int now = MIN(ZERO_BUF_SIZE, size);
+        int now = MIN(RANDOM_BUF_SIZE, size);
         size -= now;
-        spice_marshaller_add_ref(m, zero_page, now);
+        spice_marshaller_add_ref(m, random_page, now);
     }
 }

@@ -982,6 +1005,7 @@ MainChannel* main_channel_init(void)
     RedChannel *channel;
     ChannelCbs channel_cbs;

+    random_page_init();

     channel_cbs.config_socket = main_channel_config_socket;
     channel_cbs.on_disconnect = main_channel_client_on_disconnect;
-- 
1.7.6.4