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Bug #1918

Updated by Victor Julien about 8 years ago

In high networking load i noticed that packet dropped stats went above 100%. 
 I get stats like this one in example: 

 pkts :    250833 
 drop : 749860 
 drop % : 298,95% 

 What got me suspicious since i sent exactly 1M packets to Suricata, and the 
 sum of those 2 numbers is around that 1M. 

 Both pcap and pf_ring modes are affected. 
 Looking through source-pcap.c file, in lines 661-663 i found next formula : 

 <pre> 
 


 SCLogInfo("(%s) Pcap Total:%" PRIu64 " Recv:%" PRIu64 " Drop:%" PRIu64 " ( 
 %02.1f%%).", tv->name, 
 (uint64_t)pcap_s.ps_recv, (uint64_t)pcap_s.ps_recv - (uint64_t)pcap_s. 
 ps_drop, (uint64_t)pcap_s.ps_drop, 
 (((float)(uint64_t)pcap_s.ps_drop)/(float)(uint64_t)pcap_s.ps_recv)*100); 
 </pre> 


 Lurking some more i found this old patch from 2011 that I think solves 
 those stats issues where the drop% is calculated on the sum of those 2 
 values,yet here is not implemented. 

 https://redmine.openinfosecfoundation.org/attachments/628/0001-Fix-for-silly-pcap-counters-mistake-made-by-me.-ps_r.patch 


 P.S. AF-Packet correctly reports 1M total received on the NIC and drop% is 
 correct, at least it looks ok.

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