Re: [Qemu-devel] [PATCH V12 07/10] colo-compare: add TCP, UDP, ICMP packet comparison

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

On 08/31/2016 05:33 PM, Jason Wang wrote:
>
>
> On 2016年08月17日 16:10, Zhang Chen wrote:
>> We add TCP,UDP,ICMP packet comparison to replace
>> IP packet comparison. This can increase the
>> accuracy of the package comparison.
>> Less checkpoint more efficiency.
>>
>> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>   net/colo-compare.c | 152 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++--
>>   trace-events       |   4 ++
>>   2 files changed, 152 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/colo-compare.c b/net/colo-compare.c
>> index b90cf1f..0daefd9 100644
>> --- a/net/colo-compare.c
>> +++ b/net/colo-compare.c
>> @@ -18,6 +18,7 @@
>>   #include "qapi/qmp/qerror.h"
>>   #include "qapi/error.h"
>>   #include "net/net.h"
>> +#include "net/eth.h"
>>   #include "net/vhost_net.h"
>>   #include "qom/object_interfaces.h"
>>   #include "qemu/iov.h"
>> @@ -179,9 +180,136 @@ static int colo_packet_compare(Packet *ppkt, 
>> Packet *spkt)
>>       }
>>   }
>>   -static int colo_packet_compare_all(Packet *spkt, Packet *ppkt)
>> +/*
>> + * called from the compare thread on the primary
>> + * for compare tcp packet
>> + * compare_tcp copied from Dr. David Alan Gilbert's branch
>> + */
>> +static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt)
>> +{
>> +    struct tcphdr *ptcp, *stcp;
>> +    int res;
>> +    char *sdebug, *ddebug;
>> +
>> +    trace_colo_compare_main("compare tcp");
>> +    if (ppkt->size != spkt->size) {
>> +        if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
>> +            trace_colo_compare_main("pkt size not same");
>> +        }
>> +        return -1;
>> +    }
>> +
>> +    ptcp = (struct tcphdr *)ppkt->transport_header;
>> +    stcp = (struct tcphdr *)spkt->transport_header;
>> +
>> +    if (ptcp->th_seq != stcp->th_seq) {
>> +        if (trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
>> +            trace_colo_compare_main("pkt tcp seq not same");
>> +        }
>> +        return -1;
>> +    }
>> +
>> +    /*
>> +     * The 'identification' field in the IP header is *very* random
>> +     * it almost never matches.  Fudge this by ignoring differences in
>> +     * unfragmented packets; they'll normally sort themselves out if 
>> different
>> +     * anyway, and it should recover at the TCP level.
>> +     * An alternative would be to get both the primary and secondary 
>> to rewrite
>> +     * somehow; but that would need some sync traffic to sync the state
>> +     */
>> +    if (ntohs(ppkt->ip->ip_off) & IP_DF) {
>> +        spkt->ip->ip_id = ppkt->ip->ip_id;
>> +        /* and the sum will be different if the IDs were different */
>> +        spkt->ip->ip_sum = ppkt->ip->ip_sum;
>> +    }
>> +
>> +    res = memcmp(ppkt->data + ETH_HLEN, spkt->data + ETH_HLEN,
>> +                (spkt->size - ETH_HLEN));
>
> This may work but I worry about whether or not tagged packet can work 
> here. Looks like parse_packet_early() can recognize vlan tag, but 
> fill_connection_key() can not. This looks can result queuing wrong 
> packets into wrong connection.

Currently COLO proxy can't support vlan, we will add this feature in the 
future.

>
>> +
>> +    if (res != 0 && 
>> trace_event_get_state(TRACE_COLO_COMPARE_MISCOMPARE)) {
>> +        sdebug = strdup(inet_ntoa(ppkt->ip->ip_src));
>> +        ddebug = strdup(inet_ntoa(ppkt->ip->ip_dst));
>> +        fprintf(stderr, "%s: src/dst: %s/%s p: seq/ack=%u/%u"
>> +        " s: seq/ack=%u/%u res=%d flags=%x/%x\n", __func__,
>> +                   sdebug, ddebug,
>> +                   ntohl(ptcp->th_seq), ntohl(ptcp->th_ack),
>> +                   ntohl(stcp->th_seq), ntohl(stcp->th_ack),
>> +                   res, ptcp->th_flags, stcp->th_flags);
>
> I tend not mix using debug logs with tracepoints.

OK, I will change trace_colo_compare_tcp_miscompare() to fprintf() here.

Thanks
Zhang Chen

>
>> +
>> +        trace_colo_compare_tcp_miscompare("Primary len", ppkt->size);
>> +        qemu_hexdump((char *)ppkt->data, stderr, "colo-compare", 
>> ppkt->size);
>> +        trace_colo_compare_tcp_miscompare("Secondary len", spkt->size);
>> +        qemu_hexdump((char *)spkt->data, stderr, "colo-compare", 
>> spkt->size);
>> +
>> +        g_free(sdebug);
>> +        g_free(ddebug);
>> +    }
>> +
>> +    return res;
>> +}
>> +
>> +/*
>> + * called from the compare thread on the primary
>> + * for compare udp packet
>> + */
>> +static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt)
>> +{
>> +    int ret;
>> +
>> +    trace_colo_compare_main("compare udp");
>> +    ret = colo_packet_compare(ppkt, spkt);
>> +
>> +    if (ret) {
>> +        trace_colo_compare_udp_miscompare("primary pkt size", 
>> ppkt->size);
>> +        qemu_hexdump((char *)ppkt->data, stderr, "colo-compare", 
>> ppkt->size);
>> +        trace_colo_compare_udp_miscompare("Secondary pkt size", 
>> spkt->size);
>> +        qemu_hexdump((char *)spkt->data, stderr, "colo-compare", 
>> spkt->size);
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +/*
>> + * called from the compare thread on the primary
>> + * for compare icmp packet
>> + */
>> +static int colo_packet_compare_icmp(Packet *spkt, Packet *ppkt)
>> +{
>> +    int network_length;
>> +
>> +    trace_colo_compare_main("compare icmp");
>> +    network_length = ppkt->ip->ip_hl * 4;
>> +    if (ppkt->size != spkt->size ||
>> +        ppkt->size < network_length + ETH_HLEN) {
>> +        return -1;
>> +    }
>> +
>> +    if (colo_packet_compare(ppkt, spkt)) {
>> +        trace_colo_compare_icmp_miscompare("primary pkt size",
>> +                                           ppkt->size);
>> +        qemu_hexdump((char *)ppkt->data, stderr, "colo-compare",
>> +                     ppkt->size);
>> +        trace_colo_compare_icmp_miscompare("Secondary pkt size",
>> +                                           spkt->size);
>> +        qemu_hexdump((char *)spkt->data, stderr, "colo-compare",
>> +                     spkt->size);
>> +        return -1;
>> +    } else {
>> +        return 0;
>> +    }
>> +}
>> +
>> +/*
>> + * called from the compare thread on the primary
>> + * for compare other packet
>> + */
>> +static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
>>   {
>> -    trace_colo_compare_main("compare all");
>> +    trace_colo_compare_main("compare other");
>> +    trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
>> + inet_ntoa(ppkt->ip->ip_dst), spkt->size,
>> + inet_ntoa(spkt->ip->ip_src),
>> + inet_ntoa(spkt->ip->ip_dst));
>>       return colo_packet_compare(ppkt, spkt);
>>   }
>>   @@ -245,8 +373,24 @@ static void colo_compare_connection(void 
>> *opaque, void *user_data)
>>       while (!g_queue_is_empty(&conn->primary_list) &&
>>              !g_queue_is_empty(&conn->secondary_list)) {
>>           pkt = g_queue_pop_tail(&conn->primary_list);
>> -        result = g_queue_find_custom(&conn->secondary_list,
>> -                              pkt, 
>> (GCompareFunc)colo_packet_compare_all);
>> +        switch (conn->ip_proto) {
>> +        case IPPROTO_TCP:
>> +            result = g_queue_find_custom(&conn->secondary_list,
>> +                     pkt, (GCompareFunc)colo_packet_compare_tcp);
>> +            break;
>> +        case IPPROTO_UDP:
>> +            result = g_queue_find_custom(&conn->secondary_list,
>> +                     pkt, (GCompareFunc)colo_packet_compare_udp);
>> +            break;
>> +        case IPPROTO_ICMP:
>> +            result = g_queue_find_custom(&conn->secondary_list,
>> +                     pkt, (GCompareFunc)colo_packet_compare_icmp);
>> +            break;
>> +        default:
>> +            result = g_queue_find_custom(&conn->secondary_list,
>> +                     pkt, (GCompareFunc)colo_packet_compare_other);
>> +            break;
>> +        }
>>             if (result) {
>>               ret = compare_chr_send(s->chr_out, pkt->data, pkt->size);
>> diff --git a/trace-events b/trace-events
>> index 1537e91..ab22eb2 100644
>> --- a/trace-events
>> +++ b/trace-events
>> @@ -1919,5 +1919,9 @@ aspeed_vic_write(uint64_t offset, unsigned 
>> size, uint32_t data) "To 0x%" PRIx64
>>     # net/colo-compare.c
>>   colo_compare_main(const char *chr) ": %s"
>> +colo_compare_tcp_miscompare(const char *sta, int size) ": %s = %d"
>> +colo_compare_udp_miscompare(const char *sta, int size) ": %s = %d"
>> +colo_compare_icmp_miscompare(const char *sta, int size) ": %s = %d"
>>   colo_compare_ip_info(int psize, const char *sta, const char *stb, 
>> int ssize, const char *stc, const char *std) "ppkt size = %d, ip_src 
>> = %s, ip_dst = %s, spkt size = %d, ip_src = %s, ip_dst = %s"
>>   colo_old_packet_check_found(int64_t old_time) "%" PRId64
>> +colo_compare_miscompare(void) ""
>
>
>
> .
>

-- 
Thanks
zhangchen