[dpdk-dev,v2,1/2] lib/lpm:fix an issue of condition check in delete_depth_small()
Commit Message
Fixes an issue of check logic in delete_depth_small function.
For a tbl24 entry, the 'ext_entry' field indicates whether we need to use tbl8_gindex to read the next_hop from a tbl8 entry, or whether it can be read directly from this entry.
If a route is deleted, the prefix of previous route is used to override the deleted route.
When checking the depth of the previous route the conditional checks both the ext_entry and the depth, but the "else" leg fails to take account that the condition could fail for one of two possible reasons, leading to an incorrect flow when 'ext_entry == 0' is true , but 'lpm->tbl24[i].depth > depth' is false. The fix here is to add a condition check to the else leg so that it only executes when ext_entry is set.
Signed-off-by: NaNa <nana.nn@alibaba-inc.com>
---
lib/librte_lpm/rte_lpm.c | 6 ++----
1 files changed, 2 insertions(+), 4 deletions(-)
Comments
On Fri, Oct 30, 2015 at 09:14:38PM +0800, Jijiang Liu wrote:
> Fixes an issue of check logic in delete_depth_small function.
>
> For a tbl24 entry, the 'ext_entry' field indicates whether we need to use tbl8_gindex to read the next_hop from a tbl8 entry, or whether it can be read directly from this entry.
>
> If a route is deleted, the prefix of previous route is used to override the deleted route.
>
> When checking the depth of the previous route the conditional checks both the ext_entry and the depth, but the "else" leg fails to take account that the condition could fail for one of two possible reasons, leading to an incorrect flow when 'ext_entry == 0' is true , but 'lpm->tbl24[i].depth > depth' is false. The fix here is to add a condition check to the else leg so that it only executes when ext_entry is set.
>
> Signed-off-by: NaNa <nana.nn@alibaba-inc.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
@@ -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
@@ -780,8 +779,7 @@ 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