[dpdk-dev] 答复: [PATCH] lib/lpm:fix two issues in the delete_depth_small()

["洪余柯(洪余柯)" <yuke.hyk@alibaba-inc.com>]

Acked by：<fengsong> yuke.hyk@alibaba-inc.com

-----邮件原件-----
发件人: nana.nn [mailto:nana.nn@alibaba-inc.com] 
发送时间: 2015年10月28日 12:02
收件人: "洪余柯(风松)"
抄送: dev@dpdk.org; Jijiang Liu
主题: Re: [PATCH] lib/lpm:fix two issues in the delete_depth_small()

HI:
     yuke，please acked-by~ 

On Oct 28, 2015, at 11:44 AM, Jijiang Liu <jijiang.liu@intel.com> wrote:

> Fix two issues in the delete_depth_small() function.
> 
> 1> The control is not strict in this function.
> 
> In the following structure,
> struct rte_lpm_tbl24_entry {
>        union {
>                uint8_t next_hop;
>                uint8_t tbl8_gindex;
>        };
>     uint8_t ext_entry :1;
> }
> 
> When ext_entry = 0, use next_hop.only to process rte_lpm_tbl24_entry.
> 
> When ext_entry = 1, use tbl8_gindex to process the rte_lpm_tbl8_entry.
> 
> When using LPM24 + 8 algorithm, it will use ext_entry to decide to process rte_lpm_tbl24_entry structure or rte_lpm_tbl8_entry structure. 
> If a route is deleted, the prefix of previous route is used to override the deleted route. when (lpm->tbl24[i].ext_entry == 0 && lpm->tbl24[i].depth > depth) 
> it should be ignored, but due to the incorrect logic, the next_hop is used as tbl8_gindex and will process the rte_lpm_tbl8_entry.
> 
> 2> Initialization of rte_lpm_tbl8_entry is incorrect in this function 
> 
> In this function, use new rte_lpm_tbl8_entry we call A to replace the old rte_lpm_tbl8_entry. But the valid_group do not set VALID, so it will be INVALID.
> Then when adding a new route which depth is > 24,the tbl8_alloc() function will search the rte_lpm_tbl8_entrys to find INVALID valid_group, 
> and it will return the A to the add_depth_big function, so A's data is overridden.
> 
> Signed-off-by: NaNa <nana.nn@alibaba-inc.com>
> 
> ---
> lib/librte_lpm/rte_lpm.c |    7 +++----
> 1 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
> index 163ba3c..3981452 100644
> --- a/lib/librte_lpm/rte_lpm.c
> +++ b/lib/librte_lpm/rte_lpm.c
> @@ -734,8 +734,7 @@ delete_depth_small(struct rte_lpm *lpm, uint32_t ip_masked,
> 			if (lpm->tbl24[i].ext_entry == 0 &&
> 					lpm->tbl24[i].depth <= depth ) {
> 				lpm->tbl24[i].valid = INVALID;
> -			}
> -			else {
> +			} else if (lpm->tbl24[i].ext_entry == 1) {
> 				/*
> 				 * If TBL24 entry is extended, then there has
> 				 * to be a rule with depth >= 25 in the
> @@ -770,6 +769,7 @@ delete_depth_small(struct rte_lpm *lpm, uint32_t ip_masked,
> 
> 		struct rte_lpm_tbl8_entry new_tbl8_entry = {
> 			.valid = VALID,
> +			.valid_group = VALID,
> 			.depth = sub_rule_depth,
> 			.next_hop = lpm->rules_tbl
> 			[sub_rule_index].next_hop,
> @@ -780,8 +780,7 @@ delete_depth_small(struct rte_lpm *lpm, uint32_t ip_masked,
> 			if (lpm->tbl24[i].ext_entry == 0 &&
> 					lpm->tbl24[i].depth <= depth ) {
> 				lpm->tbl24[i] = new_tbl24_entry;
> -			}
> -			else {
> +			} else  if (lpm->tbl24[i].ext_entry == 1) {
> 				/*
> 				 * If TBL24 entry is extended, then there has
> 				 * to be a rule with depth >= 25 in the
> -- 
> 1.7.7.6