neigh: sysctl - simplify address calculation of gc_* variables
The code in neigh_sysctl_register() relies on a specific layout of
struct neigh_table, namely that the 'gc_*' variables are directly
following the 'parms' member in a specific order. The code, though,
expresses this in the most ugly way.
Get rid of the ugly casts and use the 'tbl' pointer to get a handle to
the table. This way we can refer to the 'gc_*' variables directly.
Similarly seen in the grsecurity patch, written by Brad Spengler.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 7277caf..47f4254 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -203,7 +203,6 @@
void (*proxy_redo)(struct sk_buff *skb);
char *id;
struct neigh_parms parms;
- /* HACK. gc_* should follow parms without a gap! */
int gc_interval;
int gc_thresh1;
int gc_thresh2;
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 32d872e..559890b 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -3059,11 +3059,12 @@
memset(&t->neigh_vars[NEIGH_VAR_GC_INTERVAL], 0,
sizeof(t->neigh_vars[NEIGH_VAR_GC_INTERVAL]));
} else {
+ struct neigh_table *tbl = p->tbl;
dev_name_source = "default";
- t->neigh_vars[NEIGH_VAR_GC_INTERVAL].data = (int *)(p + 1);
- t->neigh_vars[NEIGH_VAR_GC_THRESH1].data = (int *)(p + 1) + 1;
- t->neigh_vars[NEIGH_VAR_GC_THRESH2].data = (int *)(p + 1) + 2;
- t->neigh_vars[NEIGH_VAR_GC_THRESH3].data = (int *)(p + 1) + 3;
+ t->neigh_vars[NEIGH_VAR_GC_INTERVAL].data = &tbl->gc_interval;
+ t->neigh_vars[NEIGH_VAR_GC_THRESH1].data = &tbl->gc_thresh1;
+ t->neigh_vars[NEIGH_VAR_GC_THRESH2].data = &tbl->gc_thresh2;
+ t->neigh_vars[NEIGH_VAR_GC_THRESH3].data = &tbl->gc_thresh3;
}
if (handler) {