Date: Thu, 15 Mar 2012 19:49:28 +0000 From: =?iso-8859-1?Q?Seyit_=D6zg=FCr?= <seyit.ozgur@istanbul.net> To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Malformed syn packet cause %100 cpu and interrupts FreeBSD 9.0 release Message-ID: <3807CE6F3BF4B04EB897F4EBF2D258CE5C05F221@yuhanna.magnetdigital.local>
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Hi, Today we tried to see what happens Malformed syn packets on FreeBSD 9.0 release.. Those packets rise to CPU %100 and stucks.. listening on ix0, link-type EN10MB (Ethernet), capture size 65535 bytes 18:33:30.010215 IP vgn44-1-88-123-89-40.fbx.proxad.net > 85.xxx.xxx.90: tcp 18:33:30.010242 IP 225.74.196.88.sta.estpak.ee > 85.xxx.xxx.90: tcp 18:33:30.010269 IP Nnov-Prospekt.71.quantum.rn > 85.xxx.xxx.90: tcp 18:33:30.010296 IP host52-108-static.49-88-b.business.telecomitalia.it > 85.xxx.xxx.90: tcp 18:33:30.010325 IP 125.Red-88-1-75.dynamicIP.rima-tde.net > 85.xxx.xxx.90: tcp i dont know which tool generate those packets.. but as we see i dont see seq, flag, lenth etc.. just this ouput on tcpdump... Is there any kernel feature for do NOT process malformed syn packets ??
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