Hello, > On 27 Jan 2017, at 04:12, Nagaprabhanjan Bellaru <nagp.li...@gmail.com> wrote: > > Hi, > > I am not sure if the ping debug CLI is being actively used, but the function > "init_icmp46_echo_request" goes ahead and writes 2000 bytes into the > vlib_buffer corrupting the surrounding memory area. After 3-4 pings, vpp > always crashes.
Could you please tell a bit more about the setup (which hypervisor, which make platform - vpp/vpp_lite, which ping etc) ? I had fixed a bug with processing a vector of replies (change 4844) - might be worth verifying you do not see the symptoms of that. Now, some thoughts below, please feel free to correct me if you find an error in the below logic. My understanding is we would get the 2048 bytes of max data size in DPDK case when allocating the buffer. Minus 20 bytes for IPv4 header, minus 4 bytes for common ICMP header, minus 4 bytes for echo ID/seq, minus 8 bytes for the timestamp. That should give 2012 bytes of free space for data in IPv4 case, so for the IPv4 ping it should not overrun. The problem is of course in IPv6 case we are a few bytes short, and likewise in the vpp_lite case the VLIB_BUFFER_DATA_SIZE is 512, and we will overrun that with the static value of 2000. So the definition for PING_MAXIMUM_DATA_SIZE would need to depend on that define with appropriate subtractions... or, even better, I suppose, is to use VLIB_BUFFER_DEFAULT_FREE_LIST_BYTES since that looks to me is the define determining the max data size for a buffer. Maybe an even better option could be to just fill a vector and then use the vlib_buffer_add_data() with zero buffer index, and let it allocate and set up everything behind the scenes. What do you think ? > > Instead of copying sizeof(icmp_echo_request->data) which is 2000, it we copy > just data_len to the buffer, it should be fine? That would make the problem conditional on the CLI input for data size, so I would not say it is a much better outcome... --a > > Thanks, > -nagp > _______________________________________________ > vpp-dev mailing list > vpp-dev@lists.fd.io > https://lists.fd.io/mailman/listinfo/vpp-dev _______________________________________________ vpp-dev mailing list vpp-dev@lists.fd.io https://lists.fd.io/mailman/listinfo/vpp-dev
