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

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

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 <zhangchen.fnst@cn.fujitsu.com>
---
 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) {
-        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)
-- 
2.7.4