Missing Attachment.. On Tue, Aug 16, 2016 at 12:18 PM, Stephen Hemminger < stephen at networkplumber.org> wrote:
> On Tue, 16 Aug 2016 12:10:50 +0530 > Raja Jayapal <raja.jayapal at tcs.com> wrote: > > > Hi Nishant, > > > > Please find attachment for the pcap file. > > > > Thanks, > > Raja > > > > -----Nishant Verma <vnish11 at gmail.com> wrote: ----- > > To: Raja Jayapal <raja.jayapal at tcs.com> > > From: Nishant Verma <vnish11 at gmail.com> > > Date: 08/13/2016 02:42AM > > Cc: "users at dpdk.org" <users at dpdk.org>, Nagaratna Patagar < > nagaratna.patagar at tcs.com> > > Subject: Re: [dpdk-users] arp behaviour on dpdk > > > > Hi Raja, > > > > What i understand is that Br1(linux machine) is getting ARP request but > not sending ARP Response? > > If this is the case, it means either packet is not liked by Br1 hence > dropped or some how capture is not right. > > > > Can you share pcap file, captured at Br1. > > > > > > > > On Thu, Aug 11, 2016 at 3:02 AM, Raja Jayapal <raja.jayapal at tcs.com> > wrote: > > Hi All, > > > > I am running dpdk on KVM and would like to understand the arp behaviour > on dpdk ports. > > The topology is as below. > > > > br0(192.168.100.10)----> vnet0 -----> dpdk(NIC1- > e1000)------->dpdk(NIC2-e1000)------>vnet1----->br1(192.168.100.20) > > > > I am sending ARP packet from br0 using PackETH tool destined to br1. > > I have edited the dpdk l2fwd code in such a way that , the destination > is broadcast address(ffff). > > In br1 , i can see the arp resquest, but the host bridge is not > responding for the arp request. > > > > In br1: > > ===== > > tcpdump: verbose output suppressed, use -v or -vv for full protocol > decode > > listening on br1, link-type EN10MB (Ethernet), capture size 65535 bytes > > 12:21:15.459667 ARP, Request who-has 192.168.100.20 (00:0a:e7:2c:44:2b > (oui Unknown)) tell 192.168.100.10, length 46 > > 12:21:15.651610 ARP, Request who-has 192.168.100.20 (00:0a:e7:2c:44:2b > (oui Unknown)) tell 192.168.100.10, length 46 > > 12:21:15.867692 ARP, Request who-has 192.168.100.20 (00:0a:e7:2c:44:2b > (oui Unknown)) tell 192.168.100.10, length 46 > > > > In l2fwd application example also, the arp packets are getting received > on the adjacent ports, but the arp reply has not been sent back from br1. > > > > Could you please let me know how to make the host(br1) to reply the arp > request. > > The host kernel has a number of checks to prevent ARP spoofing. > Most likely your packet is invalid by one of these checks. > Linux ARP does not keep many statistics, so that doesn't help. > > Look at the arp_ignore sysctl flag and read kernel source for > net/ipv4/arp.c function > arp_process to see what is going on. If you are completely stuck build a > custom > kernel and instrument kernel with printk's there. > -- Rgds, Nishant
