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COLO-compare: Optimize tcp compare for option field

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In this patch we support packet that have tcp options field.
Add tcp options field check, If the packet have options
field we just skip it and compare tcp payload,
Avoid unnecessary checkpoint, optimize performance.

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Zhang Chen 2017-04-18 10:20:19 +08:00 committed by Jason Wang
parent 47bb83cad4
commit 184d4d4203
1 changed files with 26 additions and 1 deletions
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27
net/colo-compare.c
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@ -233,7 +233,32 @@ static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
spkt->ip->ip_sum = ppkt->ip->ip_sum;
}
if (ptcp->th_sum == stcp->th_sum) {
/*
* Check tcp header length for tcp option field.
* th_off > 5 means this tcp packet have options field.
* The tcp options maybe always different.
* for example:
* From RFC 7323.
* TCP Timestamps option (TSopt):
* Kind: 8
*
* Length: 10 bytes
*
* +-------+-------+---------------------+---------------------+
* |Kind=8 | 10 | TS Value (TSval) |TS Echo Reply (TSecr)|
* +-------+-------+---------------------+---------------------+
* 1 1 4 4
*
* In this case the primary guest's timestamp always different with
* the secondary guest's timestamp. COLO just focus on payload,
* so we just need skip this field.
*/
if (ptcp->th_off > 5) {
ptrdiff_t tcp_offset;
tcp_offset = ppkt->transport_header - (uint8_t *)ppkt->data
+ (ptcp->th_off * 4);
res = colo_packet_compare_common(ppkt, spkt, tcp_offset);
} else if (ptcp->th_sum == stcp->th_sum) {
res = colo_packet_compare_common(ppkt, spkt, ETH_HLEN);
} else {
res = -1;