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Re: [Qemu-devel] [PATCH 2/3] COLO-compare: Optimize colo_packet_compare_


From: Zhang Chen
Subject: Re: [Qemu-devel] [PATCH 2/3] COLO-compare: Optimize colo_packet_compare_common
Date: Mon, 27 Feb 2017 15:06:13 +0800
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1



On 02/25/2017 03:26 PM, Hailiang Zhang wrote:
On 2017/2/25 11:32, Zhang Chen wrote:
Add offset args for colo_packet_compare_common, optimize
colo_packet_compare_icmp() and colo_packet_compare_udp()
just compare the IP payload.

Signed-off-by: Zhang Chen <address@hidden>
---
  net/colo-compare.c | 28 +++++++++++++++++++++-------
  1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/net/colo-compare.c b/net/colo-compare.c
index e75f0ae..9853232 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -180,7 +180,7 @@ static int packet_enqueue(CompareState *s, int mode)
   * return:    0  means packet same
   *            > 0 || < 0 means packet different
   */
-static int colo_packet_compare_common(Packet *ppkt, Packet *spkt)
+static int colo_packet_compare_common(Packet *ppkt, Packet *spkt, int offset)
  {
trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
inet_ntoa(ppkt->ip->ip_dst), spkt->size,
@@ -188,7 +188,8 @@ static int colo_packet_compare_common(Packet *ppkt, Packet *spkt)
inet_ntoa(spkt->ip->ip_dst));

      if (ppkt->size == spkt->size) {

This check is useless, because we have done such checks in every caller.

Oh, I forgot it, not in good condition.
I will remove it in next version.

Thanks
Zhang Chen



-        return memcmp(ppkt->data, spkt->data, spkt->size);
+        return memcmp(ppkt->data + offset, spkt->data + offset,
+                      spkt->size - offset);
      } else {
          trace_colo_compare_main("Net packet size are not the same");
          return -1;
@@ -237,8 +238,7 @@ static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
          spkt->ip->ip_sum = ppkt->ip->ip_sum;
      }

-    res = memcmp(ppkt->data + ETH_HLEN, spkt->data + ETH_HLEN,
-                (spkt->size - ETH_HLEN));
+    res = colo_packet_compare_common(ppkt, spkt, ETH_HLEN);

if (res != 0 && trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
trace_colo_compare_pkt_info_src(inet_ntoa(ppkt->ip->ip_src),
@@ -277,7 +277,14 @@ static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
          return -1;
      }

-    ret = colo_packet_compare_common(ppkt, spkt);
+    /*
+     * Because of ppkt and spkt are both in the same connection,
+     * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
+ * same with spkt. In addition, IP header's Identification is a random
+     * field, we can handle it in IP fragmentation function later.
+     * So we just compare the ip payload here.
+     */
+ ret = colo_packet_compare_common(ppkt, spkt, network_length + ETH_HLEN);

      if (ret) {
trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size); @@ -304,7 +311,14 @@ static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
          return -1;
      }

-    if (colo_packet_compare_common(ppkt, spkt)) {
+    /*
+     * Because of ppkt and spkt are both in the same connection,
+     * The ppkt's src ip, dst ip, src port, dst port, ip_proto all are
+ * same with spkt. In addition, IP header's Identification is a random
+     * field, we can handle it in IP fragmentation function later.
+     * So we just compare the ip payload here.
+     */
+ if (colo_packet_compare_common(ppkt, spkt, network_length + ETH_HLEN)) {
          trace_colo_compare_icmp_miscompare("primary pkt size",
                                             ppkt->size);
          qemu_hexdump((char *)ppkt->data, stderr, "colo-compare",
@@ -330,7 +344,7 @@ static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
inet_ntoa(ppkt->ip->ip_dst), spkt->size,
inet_ntoa(spkt->ip->ip_src),
inet_ntoa(spkt->ip->ip_dst));
-    return colo_packet_compare_common(ppkt, spkt);
+    return colo_packet_compare_common(ppkt, spkt, 0);
  }

  static int colo_old_packet_check_one(Packet *pkt, int64_t *check_time)





.


--
Thanks
Zhang Chen






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