syncookie in 6.x and 7.x

[Igor Sysoev]

During testing 7.0-CURRENT I have found that it always sends syncookies
while on early FreeBSD versions "netstat -s -p tcp" always shows:

        0 cookies sent
        0 cookies received

I have looked sources and found that in early versions the sent counter
was simply not incremented at all. The patch attached.

After the patch has been applied I have found that 6 always sends
syncookies too, however, 6 unlike 7 never receives them. Why ?

Here is 6 statistics:

        1046714 syncache entries added
                28395 retransmitted
                32879 dupsyn
                0 dropped
                1038153 completed
                0 bucket overflow
                0 cache overflow
                4201 reset
                3972 stale
                0 aborted
                0 badack
                254 unreach
                0 zone failures
        1046714 cookies sent
        0 cookies received

Here is 7 statistics:

        76018 syncache entries added
                2536 retransmitted
                2574 dupsyn
                0 dropped
                75114 completed
                0 bucket overflow
                0 cache overflow
                456 reset
                267 stale
                0 aborted
                0 badack
                20 unreach
                0 zone failures
        76018 cookies sent
        24 cookies received


-- 
Igor Sysoev
http://sysoev.ru/en/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: syncookie.patch
Type: text/x-diff
Size: 330 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-net/attachments/20070816/a7fae672/syncookie.bin