El miércoles, 19 de octubre de 2016, 17:23:40 (UTC+2), emacsu...@gmail.com escribió: > El miércoles, 19 de octubre de 2016, 12:46:45 (UTC+2), Vadim Kochan > escribió:On Wed, Oct 19, 2016 at 1:38 PM, <emacsu...@gmail.com> wrote: > > > Hello. > > > > > > I'm having a problem when trying to send packets with trafgen to the > > loopback interface. > > > > > > Packets sent this way do not reach their destination. > > > > > > However, if packets are sent from an external machine, then I have no > > problem at all to receive these packets at the destination application. > > > > > > I use "-o lo" option on the command line when executing trafgen. > > > > > > I suspect the problem is that I'm building an incorrect packet, and the > > kernel is discarding it. > > > > > > The ethernet header on my cfg file looks like the following: > > > > > > -------------------------------------- > > > #include <stddef.h> > > > > > > { > > > fill(0x00, ETH_ALEN), > > > fill(0x00, ETH_ALEN), > > > c16(ETH_P_LOOP), > > > c32(0x00), > > > > > > ...... > > > > > > (Both source and destination IP addresses are set to 127.0.0.1) > > > -------------------------------------- > > > > > > I have tried other combinations, like removing the ethernet header > > completely, for instance. > > > > > > None of them worked. > > > > > > How does the ethernet header have to to look like, when you want trafgen to > > generate a valid packet to be sent thru the loopback interface? > > > > > > Thanks a lot. > > > -Bob > > > > > > -- > > > You received this message because you are subscribed to the Google Groups > > "netsniff-ng" group. > > > To unsubscribe from this group and stop receiving emails from it, send an > > email to netsniff-ng...@googlegroups.com. > > > For more options, visit https://groups.google.com/d/optout. > > > > Hi Bob, > > > > Does it work if to increase packet length to 64 bytes length ? > > > > Sorry, I have no time to check it right now, will do it later if the > > above's approach did not help. > > > > Regards, > > Vadim Kochan > > > > > > > Hi Vadim. > > > Thanks for the prompt response. > > > So far, I have been using the ETH_P_LOOP value (96), to indicate that the > packet corresponds to a loopback packet. > Given that that field is used for both type and length, if I'm understanding > you correctly, you want me to change it to a value indicating the length of > my entire packet, and not the value of ETH_P_LOOP. > I suppose you said 64 as an example, and the value there should in fact > correspond to my actual packet length. > > > I have followed this approach, but the packet does not reach my application, > still. > > > In fact, on second thoughts, I cannot see the point on using ETH_P_LOOP value > at all in the ethernet header, since its value is 96, which means that we > have to interpret that value as a length, but the packet length can be > anything. > > > Not sure if I'm missing something here .... > > > Any idea? > > > Thanks. > -Bob > > > > > > >
Hello. Any idea on why I'm not able to make traffic get to its destination thru the loopback interface? Not sure if the problem is the ethernet header I'm using. I guess so, but I have tried all combinations with no success. Thanks. -Bob -- You received this message because you are subscribed to the Google Groups "netsniff-ng" group. To unsubscribe from this group and stop receiving emails from it, send an email to netsniff-ng+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.