Update simple_pre_lag.cpp

[Devansh-567]

Fix off-by-one error in LAG index validation

Change the index boundary check in mc_set_lag_membership from > to >=. Previously, passing lag_index == LAG_MAX_ENTRIES bypassed the error check and resulted in out-of-bounds access.

[jafingerhut]

Looks reasonable to me, although it is not easy for me to find other references in the code to what the range of values is expected to be.

[Devansh-567]

Looks reasonable to me, although it is not easy for me to find other references in the code to what the range of values is expected to be.

Because C++ uses 0-based indexing for fixed-size structures, a size/count of LAG_MAX_ENTRIES means valid index values are 0 through LAG_MAX_ENTRIES - 1. Passing lag_index == LAG_MAX_ENTRIES was hitting array boundary limits, so changing > to >= catches that edge case and prevents out-of-bounds access.

[jafingerhut]

Is there a reason you wanted to close this PR without merging it?

[Devansh-567]

Is there a reason you wanted to close this PR without merging it?

Apologies for the confusion, it was accidentally closed during a branch cleanup. I have reopened this fix in PR #1444 on a clean branch.