Thanks for reply Ben. Does it mean that *miniflow_extract* will also initialize the L3 header pointer? But I am getting the correct values for *nw_proto* from the L3 header. struct ip_header *ip = dp_packet_l3(packet); nw_proto = ip->ip_proto;
Any comments on this? Whether its right or wrong? Thanks a lot for your patience and response. Regards Krish On Sat, Feb 16, 2019 at 10:09 AM Ben Pfaff <[email protected]> wrote: > You are almost certainly dereferencing a null pointer. > > On Sat, Feb 16, 2019 at 09:02:17AM +0800, Krish wrote: > > That code I showed before. It is working fine and crashing only when I > > enable debugging. > > > > As *sruct tcp_header's tcp_src* has ovs_be16 type. How to store and print > > this value ? > > > > Thanks > > > > On Sat, Feb 16, 2019, 08:43 Ben Pfaff <[email protected]> wrote: > > > > > Then you're going to have to work harder since miniflow_extract() is > > > what initializes the L4 header pointer. > > > > > > On Sat, Feb 16, 2019 at 08:39:08AM +0800, Krish wrote: > > > > I am sorry, but I am trying not to use extracted flow. I want to use > > > this > > > > information before it goes to EMC. > > > > > > > > > > > > > > > > On Sat, Feb 16, 2019, 03:44 Ben Pfaff <[email protected]> wrote: > > > > > > > > > On Fri, Feb 15, 2019 at 03:48:22PM +0800, Krish wrote: > > > > > > Hi > > > > > > > > > > > > I want to store tcp_src, dst port in a variable. > > > > > > This is what I am doing: > > > > > > 1. Retrieve packet from dp_packet_batch one by one. > > > > > > 2. Retrieving field values by extracting packets headers: > > > > > > > > > > > > struct ip_header *ip = dp_packet_l3(packet); > > > > > > nw_proto = ip->ip_proto; > > > > > > if(nw_proto == 6) > > > > > > { > > > > > > struct tcp_header *th = dp_packet_l4(packet); > > > > > > // The following are the 2 different ways I am trying to print > the > > > > > tcp_src. > > > > > > I have tried it 1 and 2 separately not at the same time. > > > > > > //1 . Ovs crash at the below statement > > > > > > uint16_t src = (uint16_t) ntohs(th->tcp_src); > > > > > > VLOG_DBG( "tcp_src ---> %d", src ); > > > > > > //2. When I enable logging ovs crashes at this > point > > > > > > VLOG_DBG( "tcp_src ---> %d", ntohs(th->tcp_src) > ); > > > > > > > > > > > > > > > > > > } > > > > > > > > > > > > Can anyone please help how to store tcp_src port value in a > variable > > > and > > > > > > print it in vlogs? > > > > > > Statement 2 is working fine if vlogs are disabled, but I want the > > > port > > > > > > value to be stored in a variable and then print. > > > > > > > > > > I'd just get it from the extracted flow instead of inventing new > code > > > to > > > > > extract it. > > > > > > > > >
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