ASSERT (p0->current_data == 0);
ip0 = (void *) (p0->data + ip_offset);
icmp0 = (void *) (p0->data + icmp_offset);
- len0 = clib_net_to_host_u16 (ip0->length) - ip4_header_bytes (ip0);
+
+ /* if IP length has been specified, then calculate the length based on buffer */
+ if (ip0->length == 0)
+ len0 = vlib_buffer_length_in_chain (vm, p0) - icmp_offset;
+ else
+ len0 = clib_net_to_host_u16 (ip0->length) - icmp_offset;
+
icmp0->checksum =
~ip_csum_fold (ip_incremental_checksum (0, icmp0, len0));
}