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>
This commit is contained in:
Mathias Krause 2014-07-12 22:36:44 +02:00 committed by David S. Miller
parent 8f2e5ae40e
commit 9ecf07a1d8
2 changed files with 5 additions and 5 deletions

View File

@ -203,7 +203,6 @@ struct neigh_table {
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;

View File

@ -3059,11 +3059,12 @@ int neigh_sysctl_register(struct net_device *dev, struct neigh_parms *p,
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) {