From: Konstantin Ananyev Date: Wed, 18 Feb 2015 16:28:49 +0000 (+0000) Subject: doc: add restrictions for ACL rule fields X-Git-Tag: spdx-start~9590 X-Git-Url: http://git.droids-corp.org/?p=dpdk.git;a=commitdiff_plain;h=fe1056d07e30666eb6789ac1f3683ba0fbb5bfb7 doc: add restrictions for ACL rule fields Signed-off-by: Konstantin Ananyev Acked-by: Siobhan Butler --- diff --git a/doc/guides/prog_guide/packet_classif_access_ctrl.rst b/doc/guides/prog_guide/packet_classif_access_ctrl.rst index 72f4510276..e018c68116 100644 --- a/doc/guides/prog_guide/packet_classif_access_ctrl.rst +++ b/doc/guides/prog_guide/packet_classif_access_ctrl.rst @@ -1,5 +1,5 @@ .. BSD LICENSE - Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + Copyright(c) 2010-2015 Intel Corporation. All rights reserved. All rights reserved. Redistribution and use in source and binary forms, with or without @@ -51,8 +51,18 @@ The library API provides the following basic operations: Overview -------- +Rule definition +~~~~~~~~~~~~~~~ + The current implementation allows the user for each AC context to specify its own rule (set of fields) over which packet classification will be performed. +Though there are few restrictions on the rule fields layout: + +* First field in the rule definition has to be one byte long. +* All subsequent fields has to be grouped into sets of 4 consecutive bytes. + +This is done mainly for performance reasons - search function processes the first input byte as part of the flow setup and then the inner loop of the search function is unrolled to process four input bytes at a time. + To define each field inside an AC rule, the following structure is used: .. code-block:: c @@ -85,10 +95,7 @@ To define each field inside an AC rule, the following structure is used: A zero-based value that represents the position of the field inside the rule; 0 to N-1 for N fields. * input_index - For performance reasons, the inner loop of the search function is unrolled to process four input bytes at a time. - This requires the input to be grouped into sets of 4 consecutive bytes. - The loop processes the first input byte as part of the setup and then - subsequent bytes must be in groups of 4 consecutive bytes. + As mentioned above, all input fields, except the very first one, must be in groups of 4 consecutive bytes. The input index specifies to which input group that field belongs to. * offset